Use dictionaries to store format specific metadata

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -10,7 +10,6 @@ using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.MetaData;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.Memory;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp.Formats.Bmp
 {
@@ -165,9 +164,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         public IImageInfo Identify(Stream stream)
         {
             this.ReadImageHeaders(stream, out _, out _);
-
+            return new ImageInfo(new PixelTypeInfo(this.infoHeader.BitsPerPixel), this.infoHeader.Width, this.infoHeader.Height, this.metaData);
-            var size = new Size(this.infoHeader.Width, this.infoHeader.Height);
-            return new BmpInfo(new PixelTypeInfo(this.infoHeader.BitsPerPixel), size, this.metaData);
         }
 
         /// <summary>

src/ImageSharp/Formats/Bmp/BmpInfo.cs

@@ -1,25 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using SixLabors.ImageSharp.MetaData;
-using SixLabors.Primitives;
-
-namespace SixLabors.ImageSharp.Formats.Bmp
-{
-    /// <summary>
-    /// Contains information about the bmp including dimensions, pixel type information and additional metadata.
-    /// </summary>
-    public class BmpInfo : ImageInfo
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="BmpInfo" /> class.
-        /// </summary>
-        /// <param name="pixelType">The image pixel type information.</param>
-        /// <param name="size">The size of the image in pixels.</param>
-        /// <param name="metaData">The images metadata.</param>
-        internal BmpInfo(PixelTypeInfo pixelType, Size size, ImageMetaData metaData)
-            : base(pixelType, size, metaData)
-        {
-        }
-    }
-}

src/ImageSharp/Formats/Gif/GifColorTableMode.cs

@@ -4,7 +4,7 @@
 namespace SixLabors.ImageSharp.Formats.Gif
 {
     /// <summary>
-    /// Provides enumeration for the available Gif color table modes.
+    /// Provides enumeration for the available color table modes.
     /// </summary>
     public enum GifColorTableMode
     {

src/ImageSharp/Formats/Gif/GifConstants.cs

@@ -26,6 +26,11 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         internal static readonly byte[] MagicNumber = Encoding.UTF8.GetBytes(FileType + FileVersion);
 
+        /// <summary>
+        /// Gets the key used for storing and retriving metadata.
+        /// </summary>
+        public const string MetaDataKey = FileType;
+
         /// <summary>
         /// The extension block introducer <value>!</value>.
         /// </summary>
@@ -41,20 +46,25 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         public const byte ApplicationExtensionLabel = 0xFF;
 
+        /// <summary>
+        /// The application block size.
+        /// </summary>
+        public const byte ApplicationBlockSize = 11;
+
         /// <summary>
         /// The application identification.
         /// </summary>
-        public const string ApplicationIdentification = "NETSCAPE2.0";
+        public const string NetscapeApplicationIdentification = "NETSCAPE2.0";
 
         /// <summary>
         /// The ASCII encoded application identification bytes.
         /// </summary>
-        internal static readonly byte[] ApplicationIdentificationBytes = Encoding.UTF8.GetBytes(ApplicationIdentification);
+        internal static readonly byte[] NetscapeApplicationIdentificationBytes = Encoding.UTF8.GetBytes(NetscapeApplicationIdentification);
 
         /// <summary>
-        /// The application block size.
+        /// The Netscape looping application sub block size.
         /// </summary>
-        public const byte ApplicationBlockSize = 11;
+        public const byte NetscapeLoopingSubBlockSize = 3;
 
         /// <summary>
         /// The comment label.

src/ImageSharp/Formats/Gif/GifDecoder.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Text;
+using SixLabors.ImageSharp.MetaData;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Gif

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -61,10 +61,15 @@ namespace SixLabors.ImageSharp.Formats.Gif
         private GifImageDescriptor imageDescriptor;
 
         /// <summary>
-        /// The metadata
+        /// The abstract metadata.
         /// </summary>
         private ImageMetaData metaData;
 
+        /// <summary>
+        /// The gif specific metadata.
+        /// </summary>
+        private GifMetaData gifMetaData;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="GifDecoderCore"/> class.
         /// </summary>
@@ -134,11 +139,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                                 this.ReadComments();
                                 break;
                             case GifConstants.ApplicationExtensionLabel:
-
+                                this.ReadApplicationExtension();
-                                // The application extension length should be 11 but we've got test images that incorrectly
-                                // set this to 252.
-                                int appLength = stream.ReadByte();
-                                this.Skip(appLength); // No need to read.
                                 break;
                             case GifConstants.PlainTextLabel:
                                 int plainLength = stream.ReadByte();
@@ -163,6 +164,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 this.globalColorTable?.Dispose();
             }
 
+            image?.MetaData.AddOrUpdateGifMetaData(this.gifMetaData);
             return image;
         }
 
@@ -197,11 +199,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                                 this.ReadComments();
                                 break;
                             case GifConstants.ApplicationExtensionLabel:
-
+                                this.ReadApplicationExtension();
-                                // The application extension length should be 11 but we've got test images that incorrectly
-                                // set this to 252.
-                                int appLength = stream.ReadByte();
-                                this.Skip(appLength); // No need to read.
                                 break;
                             case GifConstants.PlainTextLabel:
                                 int plainLength = stream.ReadByte();
@@ -226,16 +224,11 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 this.globalColorTable?.Dispose();
             }
 
-            GifColorTableMode colorTableMode = this.logicalScreenDescriptor.GlobalColorTableFlag
+            this.metaData.AddOrUpdateGifMetaData(this.gifMetaData);
-            ? GifColorTableMode.Global
+            return new ImageInfo(
-            : GifColorTableMode.Local;
-
-            var size = new Size(this.logicalScreenDescriptor.Width, this.logicalScreenDescriptor.Height);
-
-            return new GifInfo(
-                colorTableMode,
                 new PixelTypeInfo(this.logicalScreenDescriptor.BitsPerPixel),
-                size,
+                this.logicalScreenDescriptor.Width,
+                this.logicalScreenDescriptor.Height,
                 this.metaData);
         }
 
@@ -269,6 +262,41 @@ namespace SixLabors.ImageSharp.Formats.Gif
             this.logicalScreenDescriptor = GifLogicalScreenDescriptor.Parse(this.buffer);
         }
 
+        /// <summary>
+        /// Reads the application extension block parsing any animation information
+        /// if present.
+        /// </summary>
+        private void ReadApplicationExtension()
+        {
+            int appLength = this.stream.ReadByte();
+
+            // If the length is 11 then it's a valid extension and most likely
+            // a NETSCAPE or ANIMEXTS extension. We want the loop count from this.
+            if (appLength == GifConstants.ApplicationBlockSize)
+            {
+                this.stream.Skip(appLength);
+                int subBlockSize = this.stream.ReadByte();
+
+                // TODO: There's also a NETSCAPE buffer extension.
+                // http://www.vurdalakov.net/misc/gif/netscape-buffering-application-extension
+                if (subBlockSize == GifConstants.NetscapeLoopingSubBlockSize)
+                {
+                    this.stream.Read(this.buffer, 0, GifConstants.NetscapeLoopingSubBlockSize);
+                    this.gifMetaData.RepeatCount = GifNetscapeLoopingApplicationExtension.Parse(this.buffer.AsSpan(1)).RepeatCount;
+                    this.stream.Skip(1); // Skip the terminator.
+                    return;
+                }
+
+                // Could be XMP or something else not supported yet.
+                // Back up and skip.
+                this.stream.Position -= appLength + 1;
+                this.Skip(appLength);
+                return;
+            }
+
+            this.Skip(appLength); // Not supported by any known decoder.
+        }
+
         /// <summary>
         /// Skips the designated number of bytes in the stream.
         /// </summary>
@@ -399,7 +427,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
             }
             else
             {
-                if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToPrevious)
+                if (this.graphicsControlExtension.DisposalMethod == GifDisposalMethod.RestoreToPrevious)
                 {
                     prevFrame = previousFrame;
                 }
@@ -482,7 +510,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
 
             previousFrame = currentFrame ?? image.Frames.RootFrame;
 
-            if (this.graphicsControlExtension.DisposalMethod == DisposalMethod.RestoreToBackground)
+            if (this.graphicsControlExtension.DisposalMethod == GifDisposalMethod.RestoreToBackground)
             {
                 this.restoreArea = new Rectangle(descriptor.Left, descriptor.Top, descriptor.Width, descriptor.Height);
             }
@@ -514,24 +542,26 @@ namespace SixLabors.ImageSharp.Formats.Gif
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private void SetFrameMetaData(ImageFrameMetaData meta)
         {
+            var gifMeta = new GifFrameMetaData();
             if (this.graphicsControlExtension.DelayTime > 0)
             {
-                meta.FrameDelay = this.graphicsControlExtension.DelayTime;
+                gifMeta.FrameDelay = this.graphicsControlExtension.DelayTime;
             }
 
             // Frames can either use the global table or their own local table.
             if (this.logicalScreenDescriptor.GlobalColorTableFlag
                 && this.logicalScreenDescriptor.GlobalColorTableSize > 0)
             {
-                meta.ColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize;
+                gifMeta.ColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize;
             }
             else if (this.imageDescriptor.LocalColorTableFlag
                 && this.imageDescriptor.LocalColorTableSize > 0)
             {
-                meta.ColorTableLength = this.imageDescriptor.LocalColorTableSize;
+                gifMeta.ColorTableLength = this.imageDescriptor.LocalColorTableSize;
             }
 
-            meta.DisposalMethod = this.graphicsControlExtension.DisposalMethod;
+            gifMeta.DisposalMethod = this.graphicsControlExtension.DisposalMethod;
+            meta.AddOrUpdateGifFrameMetaData(gifMeta);
         }
 
         /// <summary>
@@ -575,10 +605,17 @@ namespace SixLabors.ImageSharp.Formats.Gif
             }
 
             this.metaData = meta;
+            this.gifMetaData = new GifMetaData
+            {
+                ColorTableMode = this.logicalScreenDescriptor.GlobalColorTableFlag
+                ? GifColorTableMode.Global
+                : GifColorTableMode.Local
+            };
 
             if (this.logicalScreenDescriptor.GlobalColorTableFlag)
             {
                 int globalColorTableLength = this.logicalScreenDescriptor.GlobalColorTableSize * 3;
+                this.gifMetaData.GlobalColorTableLength = globalColorTableLength;
 
                 this.globalColorTable = this.MemoryAllocator.AllocateManagedByteBuffer(globalColorTableLength, AllocationOptions.Clean);
 

src/ImageSharp/Formats/Gif/DisposalMethod.cs → src/ImageSharp/Formats/Gif/GifDisposalMethod.cs

@@ -8,7 +8,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
     /// in an animation sequence.
     /// <see href="http://www.w3.org/Graphics/GIF/spec-gif89a.txt"/> section 23
     /// </summary>
-    public enum DisposalMethod
+    public enum GifDisposalMethod
     {
         /// <summary>
         /// No disposal specified.

src/ImageSharp/Formats/Gif/GifEncoder.cs

@@ -33,7 +33,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// Gets or sets the color table mode: Global or local.
         /// </summary>
-        public GifColorTableMode ColorTableMode { get; set; }
+        public GifColorTableMode? ColorTableMode { get; set; }
 
         /// <inheritdoc/>
         public void Encode<TPixel>(Image<TPixel> image, Stream stream)

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.Buffers.Binary;
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -44,7 +43,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// The color table mode: Global or local.
         /// </summary>
-        private readonly GifColorTableMode colorTableMode;
+        private GifColorTableMode? colorTableMode;
 
         /// <summary>
         /// A flag indicating whether to ingore the metadata when writing the image.
@@ -56,6 +55,11 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         private int bitDepth;
 
+        /// <summary>
+        /// Gif specific meta data.
+        /// </summary>
+        private GifMetaData gifMetaData;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="GifEncoderCore"/> class.
         /// </summary>
@@ -66,7 +70,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
             this.memoryAllocator = memoryAllocator;
             this.textEncoding = options.TextEncoding ?? GifConstants.DefaultEncoding;
             this.quantizer = options.Quantizer;
-            this.colorTableMode = options.ColorTableMode;
             this.ignoreMetadata = options.IgnoreMetadata;
         }
 
@@ -82,6 +85,10 @@ namespace SixLabors.ImageSharp.Formats.Gif
             Guard.NotNull(image, nameof(image));
             Guard.NotNull(stream, nameof(stream));
 
+            this.gifMetaData = image.MetaData.GetGifMetaData() ?? new GifMetaData();
+            this.colorTableMode = this.colorTableMode ?? this.gifMetaData.ColorTableMode;
+            bool useGlobalTable = this.colorTableMode.Equals(GifColorTableMode.Global);
+
             // Quantize the image returning a palette.
             QuantizedFrame<TPixel> quantized =
                 this.quantizer.CreateFrameQuantizer<TPixel>().QuantizeFrame(image.Frames.RootFrame);
@@ -94,7 +101,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
 
             // Write the LSD.
             int index = this.GetTransparentIndex(quantized);
-            bool useGlobalTable = this.colorTableMode.Equals(GifColorTableMode.Global);
             this.WriteLogicalScreenDescriptor(image, index, useGlobalTable, stream);
 
             if (useGlobalTable)
@@ -108,7 +114,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
             // Write application extension to allow additional frames.
             if (image.Frames.Count > 1)
             {
-                this.WriteApplicationExtension(stream, image.MetaData.RepeatCount);
+                this.WriteApplicationExtension(stream, this.gifMetaData.RepeatCount);
             }
 
             if (useGlobalTable)
@@ -136,8 +142,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
             for (int i = 0; i < image.Frames.Count; i++)
             {
                 ImageFrame<TPixel> frame = image.Frames[i];
-
+                GifFrameMetaData frameMetaData = frame.MetaData.GetGifFrameMetaData() ?? new GifFrameMetaData();
-                this.WriteGraphicalControlExtension(frame.MetaData, transparencyIndex, stream);
+                this.WriteGraphicalControlExtension(frameMetaData, transparencyIndex, stream);
                 this.WriteImageDescriptor(frame, false, stream);
 
                 if (i == 0)
@@ -159,16 +165,18 @@ namespace SixLabors.ImageSharp.Formats.Gif
             where TPixel : struct, IPixel<TPixel>
         {
             ImageFrame<TPixel> previousFrame = null;
+            GifFrameMetaData previousMeta = null;
             foreach (ImageFrame<TPixel> frame in image.Frames)
             {
+                GifFrameMetaData meta = frame.MetaData.GetGifFrameMetaData() ?? new GifFrameMetaData();
                 if (quantized is null)
                 {
                     // Allow each frame to be encoded at whatever color depth the frame designates if set.
                     if (previousFrame != null
-                        && previousFrame.MetaData.ColorTableLength != frame.MetaData.ColorTableLength
+                        && previousMeta.ColorTableLength != meta.ColorTableLength
-                        && frame.MetaData.ColorTableLength > 0)
+                        && meta.ColorTableLength > 0)
                     {
-                        quantized = this.quantizer.CreateFrameQuantizer<TPixel>(frame.MetaData.ColorTableLength).QuantizeFrame(frame);
+                        quantized = this.quantizer.CreateFrameQuantizer<TPixel>(meta.ColorTableLength).QuantizeFrame(frame);
                     }
                     else
                     {
@@ -177,7 +185,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 }
 
                 this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
-                this.WriteGraphicalControlExtension(frame.MetaData, this.GetTransparentIndex(quantized), stream);
+                this.WriteGraphicalControlExtension(meta, this.GetTransparentIndex(quantized), stream);
                 this.WriteImageDescriptor(frame, true, stream);
                 this.WriteColorTable(quantized, stream);
                 this.WriteImageData(quantized, stream);
@@ -185,6 +193,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 quantized?.Dispose();
                 quantized = null; // So next frame can regenerate it
                 previousFrame = frame;
+                previousMeta = meta;
             }
         }
 
@@ -290,25 +299,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
             // Application Extension Header
             if (repeatCount != 1)
             {
-                this.buffer[0] = GifConstants.ExtensionIntroducer;
+                var loopingExtension = new GifNetscapeLoopingApplicationExtension(repeatCount);
-                this.buffer[1] = GifConstants.ApplicationExtensionLabel;
+                this.WriteExtension(loopingExtension, stream);
-                this.buffer[2] = GifConstants.ApplicationBlockSize;
-
-                // Write NETSCAPE2.0
-                GifConstants.ApplicationIdentificationBytes.AsSpan().CopyTo(this.buffer.AsSpan(3, 11));
-
-                // Application Data ----
-                this.buffer[14] = 3; // Application block length
-                this.buffer[15] = 1; // Data sub-block index (always 1)
-
-                // 0 means loop indefinitely. Count is set as play n + 1 times.
-                repeatCount = (ushort)Math.Max(0, repeatCount - 1);
-
-                BinaryPrimitives.WriteUInt16LittleEndian(this.buffer.AsSpan(16, 2), repeatCount); // Repeat count for images.
-
-                this.buffer[18] = GifConstants.Terminator; // Terminator
-
-                stream.Write(this.buffer, 0, 19);
             }
         }
 
@@ -348,7 +340,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <param name="metaData">The metadata of the image or frame.</param>
         /// <param name="transparencyIndex">The index of the color in the color palette to make transparent.</param>
         /// <param name="stream">The stream to write to.</param>
-        private void WriteGraphicalControlExtension(ImageFrameMetaData metaData, int transparencyIndex, Stream stream)
+        private void WriteGraphicalControlExtension(GifFrameMetaData metaData, int transparencyIndex, Stream stream)
         {
             byte packedValue = GifGraphicControlExtension.GetPackedValue(
                 disposalMethod: metaData.DisposalMethod,

src/ImageSharp/Formats/Gif/GifFrameMetaData.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Gif
+{
+    /// <summary>
+    /// Provides Gif specific metadata information for the image frame.
+    /// </summary>
+    public class GifFrameMetaData
+    {
+        /// <summary>
+        /// Gets or sets the length of the color table for paletted images.
+        /// If not 0, then this field indicates the maximum number of colors to use when quantizing the
+        /// image frame.
+        /// </summary>
+        public int ColorTableLength { get; set; }
+
+        /// <summary>
+        /// Gets or sets the frame delay for animated images.
+        /// If not 0, when utilized in Gif animation, this field specifies the number of hundredths (1/100) of a second to
+        /// wait before continuing with the processing of the Data Stream.
+        /// The clock starts ticking immediately after the graphic is rendered.
+        /// </summary>
+        public int FrameDelay { get; set; }
+
+        /// <summary>
+        /// Gets or sets the disposal method for animated images.
+        /// Primarily used in Gif animation, this field indicates the way in which the graphic is to
+        /// be treated after being displayed.
+        /// </summary>
+        public GifDisposalMethod DisposalMethod { get; set; }
+    }
+}

src/ImageSharp/Formats/Gif/GifInfo.cs

@@ -1,33 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using SixLabors.ImageSharp.MetaData;
-using SixLabors.Primitives;
-
-namespace SixLabors.ImageSharp.Formats.Gif
-{
-    /// <summary>
-    /// Contains information about the bmp including dimensions, pixel type information and additional metadata.
-    /// </summary>
-    public class GifInfo : ImageInfo
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="GifInfo" /> class.
-        /// </summary>
-        /// <param name="colorTableMode">The color table mode.</param>
-        /// <param name="pixelType">The image pixel type information.</param>
-        /// <param name="size">The size of the image in pixels.</param>
-        /// <param name="metaData">The images metadata.</param>
-        internal GifInfo(
-            GifColorTableMode colorTableMode,
-            PixelTypeInfo pixelType,
-            Size size,
-            ImageMetaData metaData)
-            : base(pixelType, size, metaData) => this.ColorTableMode = colorTableMode;
-
-        /// <summary>
-        /// Gets the color table mode.
-        /// </summary>
-        public GifColorTableMode ColorTableMode { get; }
-    }
-}

src/ImageSharp/Formats/Gif/GifMetaData.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Formats.Gif
+{
+    /// <summary>
+    /// Provides Gif specific metadata information for the image.
+    /// </summary>
+    public class GifMetaData
+    {
+        /// <summary>
+        /// Gets or sets the number of times any animation is repeated.
+        /// <remarks>
+        /// 0 means to repeat indefinitely, count is set as play n + 1 times
+        /// </remarks>
+        /// </summary>
+        public ushort RepeatCount { get; set; }
+
+        /// <summary>
+        /// Gets or sets the color table mode.
+        /// </summary>
+        public GifColorTableMode ColorTableMode { get; set; }
+
+        /// <summary>
+        /// Gets or sets the length of the global color table if present.
+        /// </summary>
+        public int GlobalColorTableLength { get; set; }
+    }
+}

src/ImageSharp/Formats/Gif/GifMetaDataExtensions.cs

@@ -0,0 +1,49 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.MetaData;
+
+namespace SixLabors.ImageSharp.Formats.Gif
+{
+    /// <summary>
+    /// Extension methods for storing meta data specific to Gif images.
+    /// </summary>
+    public static class GifMetaDataExtensions
+    {
+        /// <summary>
+        /// Adds or updates the Gif specific meta data to the image.
+        /// </summary>
+        /// <param name="meta">The image meta data.</param>
+        /// <param name="value">The gif meta data.</param>
+        public static void AddOrUpdateGifMetaData(this ImageMetaData meta, GifMetaData value) => meta.AddOrUpdateMetaData(GifConstants.MetaDataKey, value);
+
+        /// <summary>
+        /// Gets the Gif format specific meta data from the image.
+        /// </summary>
+        /// <param name="meta">The image meta data.</param>
+        /// <returns>The <see cref="GifMetaData"/> or null.</returns>
+        public static GifMetaData GetGifMetaData(this ImageMetaData meta)
+        {
+            meta.TryGetMetaData(GifConstants.MetaDataKey, out GifMetaData value);
+            return value;
+        }
+
+        /// <summary>
+        /// Adds or updates the Gif specific meta data to the image frame.
+        /// </summary>
+        /// <param name="meta">The image meta data.</param>
+        /// <param name="value">The gif meta data.</param>
+        public static void AddOrUpdateGifFrameMetaData(this ImageFrameMetaData meta, GifFrameMetaData value) => meta.AddOrUpdateMetaData(GifConstants.MetaDataKey, value);
+
+        /// <summary>
+        /// Gets the Gif format specific meta data from the image frame.
+        /// </summary>
+        /// <param name="meta">The image meta data.</param>
+        /// <returns>The <see cref="GifMetaData"/> or null.</returns>
+        public static GifFrameMetaData GetGifFrameMetaData(this ImageFrameMetaData meta)
+        {
+            meta.TryGetMetaData(GifConstants.MetaDataKey, out GifFrameMetaData value);
+            return value;
+        }
+    }
+}

src/ImageSharp/Formats/Gif/IGifDecoderOptions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.Text;
+using SixLabors.ImageSharp.MetaData;
 
 namespace SixLabors.ImageSharp.Formats.Gif
 {

src/ImageSharp/Formats/Gif/IGifEncoderOptions.cs

@@ -29,6 +29,6 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// Gets the color table mode: Global or local.
         /// </summary>
-        GifColorTableMode ColorTableMode { get; }
+        GifColorTableMode? ColorTableMode { get; }
     }
 }

src/ImageSharp/Formats/Gif/Sections/GifGraphicControlExtension.cs

@@ -53,7 +53,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// Gets the disposal method which indicates the way in which the
         /// graphic is to be treated after being displayed.
         /// </summary>
-        public DisposalMethod DisposalMethod => (DisposalMethod)((this.Packed & 0x1C) >> 2);
+        public GifDisposalMethod DisposalMethod => (GifDisposalMethod)((this.Packed & 0x1C) >> 2);
 
         /// <summary>
         /// Gets a value indicating whether transparency flag is to be set.
@@ -77,7 +77,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
             return MemoryMarshal.Cast<byte, GifGraphicControlExtension>(buffer)[0];
         }
 
-        public static byte GetPackedValue(DisposalMethod disposalMethod, bool userInputFlag = false, bool transparencyFlag = false)
+        public static byte GetPackedValue(GifDisposalMethod disposalMethod, bool userInputFlag = false, bool transparencyFlag = false)
         {
             /*
             Reserved               | 3 Bits

src/ImageSharp/Formats/Gif/Sections/GifNetscapeLoopingApplicationExtension.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers.Binary;
+
+namespace SixLabors.ImageSharp.Formats.Gif
+{
+    internal readonly struct GifNetscapeLoopingApplicationExtension : IGifExtension
+    {
+        public GifNetscapeLoopingApplicationExtension(ushort repeatCount) => this.RepeatCount = repeatCount;
+
+        public byte Label => GifConstants.ApplicationExtensionLabel;
+
+        /// <summary>
+        /// Gets the repeat count.
+        /// 0 means loop indefinitely. Count is set as play n + 1 times.
+        /// </summary>
+        public ushort RepeatCount { get; }
+
+        public static GifNetscapeLoopingApplicationExtension Parse(ReadOnlySpan<byte> buffer)
+        {
+            ushort repeatCount = BinaryPrimitives.ReadUInt16LittleEndian(buffer.Slice(0, 2));
+            return new GifNetscapeLoopingApplicationExtension(repeatCount);
+        }
+
+        public int WriteTo(Span<byte> buffer)
+        {
+            buffer[0] = GifConstants.ApplicationBlockSize;
+
+            // Write NETSCAPE2.0
+            GifConstants.NetscapeApplicationIdentificationBytes.AsSpan().CopyTo(buffer.Slice(1, 11));
+
+            // Application Data ----
+            buffer[12] = 3; // Application block length (always 3)
+            buffer[13] = 1; // Data sub-block indentity (always 1)
+
+            // 0 means loop indefinitely. Count is set as play n + 1 times.
+            BinaryPrimitives.WriteUInt16LittleEndian(buffer.Slice(14, 2), this.RepeatCount);
+
+            return 16; // Length - Introducer + Label + Terminator.
+        }
+    }
+}

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -235,7 +235,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             this.InitIccProfile();
             this.InitDerivedMetaDataProperties();
 
-            return new JpegInfo(new PixelTypeInfo(this.BitsPerPixel), new Size(this.ImageWidth, this.ImageHeight), this.MetaData);
+            return new ImageInfo(new PixelTypeInfo(this.BitsPerPixel), this.ImageWidth, this.ImageHeight, this.MetaData);
         }
 
         /// <summary>

src/ImageSharp/Formats/Jpeg/JpegInfo.cs

@@ -1,25 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using SixLabors.ImageSharp.MetaData;
-using SixLabors.Primitives;
-
-namespace SixLabors.ImageSharp.Formats.Jpeg
-{
-    /// <summary>
-    /// Contains information about the bmp including dimensions, pixel type information and additional metadata.
-    /// </summary>
-    public class JpegInfo : ImageInfo
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="JpegInfo" /> class.
-        /// </summary>
-        /// <param name="pixelType">The image pixel type information.</param>
-        /// <param name="size">The size of the image in pixels.</param>
-        /// <param name="metaData">The images metadata.</param>
-        internal JpegInfo(PixelTypeInfo pixelType, Size size, ImageMetaData metaData)
-            : base(pixelType, size, metaData)
-        {
-        }
-    }
-}

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -17,7 +17,6 @@ using SixLabors.ImageSharp.MetaData;
 using SixLabors.ImageSharp.MetaData.Profiles.Exif;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.Memory;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp.Formats.Png
 {
@@ -349,7 +348,7 @@ namespace SixLabors.ImageSharp.Formats.Png
                 throw new ImageFormatException("PNG Image does not contain a header chunk");
             }
 
-            return new PngInfo(new PixelTypeInfo(this.CalculateBitsPerPixel()), new Size(this.header.Width, this.header.Height), metadata);
+            return new ImageInfo(new PixelTypeInfo(this.CalculateBitsPerPixel()), this.header.Width, this.header.Height, metadata);
         }
 
         /// <summary>

src/ImageSharp/Formats/Png/PngInfo.cs

@@ -1,25 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using SixLabors.ImageSharp.MetaData;
-using SixLabors.Primitives;
-
-namespace SixLabors.ImageSharp.Formats.Png
-{
-    /// <summary>
-    /// Contains information about the bmp including dimensions, pixel type information and additional metadata.
-    /// </summary>
-    public class PngInfo : ImageInfo
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="PngInfo" /> class.
-        /// </summary>
-        /// <param name="pixelType">The image pixel type information.</param>
-        /// <param name="size">The size of the image in pixels.</param>
-        /// <param name="metaData">The images metadata.</param>
-        internal PngInfo(PixelTypeInfo pixelType, Size size, ImageMetaData metaData)
-            : base(pixelType, size, metaData)
-        {
-        }
-    }
-}

src/ImageSharp/ImageInfo.cs

@@ -3,26 +3,26 @@
 
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.MetaData;
-using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp
 {
     /// <summary>
     /// Contains information about the image including dimensions, pixel type information and additional metadata
     /// </summary>
-    public abstract class ImageInfo : IImageInfo
+    internal sealed class ImageInfo : IImageInfo
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="ImageInfo"/> class.
         /// </summary>
         /// <param name="pixelType">The image pixel type information.</param>
-        /// <param name="size">The size of the image in pixels.</param>
+        /// <param name="width">The width of the image in pixels.</param>
+        /// <param name="height">The height of the image in pixels.</param>
         /// <param name="metaData">The images metadata.</param>
-        protected ImageInfo(PixelTypeInfo pixelType, Size size, ImageMetaData metaData)
+        public ImageInfo(PixelTypeInfo pixelType, int width, int height, ImageMetaData metaData)
         {
             this.PixelType = pixelType;
-            this.Width = size.Width;
+            this.Width = width;
-            this.Height = size.Height;
+            this.Height = height;
             this.MetaData = metaData;
         }
 

src/ImageSharp/Formats/Gif/FrameDecodingMode.cs → src/ImageSharp/MetaData/FrameDecodingMode.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-namespace SixLabors.ImageSharp.Formats.Gif
+namespace SixLabors.ImageSharp.MetaData
 {
     /// <summary>
     /// Enumerated frame process modes to apply to multi-frame images.

src/ImageSharp/MetaData/ImageFrameMetaData.cs

@@ -1,7 +1,8 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using SixLabors.ImageSharp.Formats.Gif;
+using System;
+using System.Collections.Generic;
 
 namespace SixLabors.ImageSharp.MetaData
 {
@@ -10,6 +11,8 @@ namespace SixLabors.ImageSharp.MetaData
     /// </summary>
     public sealed class ImageFrameMetaData
     {
+        private readonly Dictionary<string, object> metaData = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ImageFrameMetaData"/> class.
         /// </summary>
@@ -28,37 +31,57 @@ namespace SixLabors.ImageSharp.MetaData
         {
             DebugGuard.NotNull(other, nameof(other));
 
-            this.ColorTableLength = other.ColorTableLength;
+            foreach (KeyValuePair<string, object> meta in other.metaData)
-            this.FrameDelay = other.FrameDelay;
+            {
-            this.DisposalMethod = other.DisposalMethod;
+                this.metaData.Add(meta.Key, meta.Value);
+            }
         }
 
         /// <summary>
-        /// Gets or sets the length of the color table for paletted images.
+        /// Clones this ImageFrameMetaData.
-        /// If not 0, then this field indicates the maximum number of colors to use when quantizing the
-        /// image frame.
         /// </summary>
-        public int ColorTableLength { get; set; }
+        /// <returns>The cloned instance.</returns>
+        public ImageFrameMetaData Clone() => new ImageFrameMetaData(this);
 
         /// <summary>
-        /// Gets or sets the frame delay for animated images.
+        /// Adds or updates the specified key and value to the <see cref="ImageMetaData"/>.
-        /// If not 0, when utilized in Gif animation, this field specifies the number of hundredths (1/100) of a second to
-        /// wait before continuing with the processing of the Data Stream.
-        /// The clock starts ticking immediately after the graphic is rendered.
         /// </summary>
-        public int FrameDelay { get; set; }
+        /// <param name="key">The key of the metadata to add.</param>
+        /// <param name="value">The value of the element to add.</param>
+        /// <exception cref="ArgumentNullException">key is null.</exception>
+        /// <exception cref="ArgumentNullException">value is null.</exception>
+        /// <exception cref="ArgumentException">An element with the same key already exists in the <see cref="ImageMetaData"/>.</exception>
+        public void AddOrUpdateMetaData(string key, object value)
+        {
+            // Don't think this needs to be threadsafe.
+            Guard.NotNull(value, nameof(value));
+            this.metaData[key] = value;
+        }
 
         /// <summary>
-        /// Gets or sets the disposal method for animated images.
+        /// Gets the metadata value associated with the specified key.
-        /// Primarily used in Gif animation, this field indicates the way in which the graphic is to
-        /// be treated after being displayed.
         /// </summary>
-        public DisposalMethod DisposalMethod { get; set; }
+        /// <typeparam name="T">The type of value.</typeparam>
+        /// <param name="key">The key of the value to get.</param>
+        /// <param name="value">
+        /// When this method returns, contains the metadata value associated with the specified key,
+        /// if the key is found; otherwise, the default value for the type of the value parameter.
+        /// This parameter is passed uninitialized.
+        /// </param>
+        /// <returns>
+        /// true if the <see cref="ImageMetaData"/> contains an element with
+        /// the specified key; otherwise, false.
+        /// </returns>
+        public bool TryGetMetaData<T>(string key, out T value)
+        {
+            if (this.metaData.TryGetValue(key, out object meta))
+            {
+                value = (T)meta;
+                return true;
+            }
 
-        /// <summary>
+            value = default;
-        /// Clones this ImageFrameMetaData.
+            return false;
-        /// </summary>
+        }
-        /// <returns>The cloned instance.</returns>
-        public ImageFrameMetaData Clone() => new ImageFrameMetaData(this);
     }
 }

src/ImageSharp/MetaData/ImageMetaData.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using System.Collections.Generic;
 using SixLabors.ImageSharp.MetaData.Profiles.Exif;
 using SixLabors.ImageSharp.MetaData.Profiles.Icc;
@@ -24,6 +25,7 @@ namespace SixLabors.ImageSharp.MetaData
         /// </summary>
         public const double DefaultVerticalResolution = 96;
 
+        private readonly Dictionary<string, object> metaData = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
         private double horizontalResolution;
         private double verticalResolution;
 
@@ -48,7 +50,11 @@ namespace SixLabors.ImageSharp.MetaData
             this.HorizontalResolution = other.HorizontalResolution;
             this.VerticalResolution = other.VerticalResolution;
             this.ResolutionUnits = other.ResolutionUnits;
-            this.RepeatCount = other.RepeatCount;
+
+            foreach (KeyValuePair<string, object> meta in other.metaData)
+            {
+                this.metaData.Add(meta.Key, meta.Value);
+            }
 
             foreach (ImageProperty property in other.Properties)
             {
@@ -125,10 +131,51 @@ namespace SixLabors.ImageSharp.MetaData
         public IList<ImageProperty> Properties { get; } = new List<ImageProperty>();
 
         /// <summary>
-        /// Gets or sets the number of times any animation is repeated.
+        /// Adds or updates the specified key and value to the <see cref="ImageMetaData"/>.
-        /// <remarks>0 means to repeat indefinitely.</remarks>
+        /// </summary>
+        /// <param name="key">The key of the metadata to add.</param>
+        /// <param name="value">The value of the element to add.</param>
+        /// <exception cref="ArgumentNullException">key is null.</exception>
+        /// <exception cref="ArgumentNullException">value is null.</exception>
+        /// <exception cref="ArgumentException">An element with the same key already exists in the <see cref="ImageMetaData"/>.</exception>
+        public void AddOrUpdateMetaData(string key, object value)
+        {
+            // Don't think this needs to be threadsafe.
+            Guard.NotNull(value, nameof(value));
+            this.metaData[key] = value;
+        }
+
+        /// <summary>
+        /// Gets the metadata value associated with the specified key.
         /// </summary>
-        public ushort RepeatCount { get; set; }
+        /// <typeparam name="T">The type of value.</typeparam>
+        /// <param name="key">The key of the value to get.</param>
+        /// <param name="value">
+        /// When this method returns, contains the metadata value associated with the specified key,
+        /// if the key is found; otherwise, the default value for the type of the value parameter.
+        /// This parameter is passed uninitialized.
+        /// </param>
+        /// <returns>
+        /// true if the <see cref="ImageMetaData"/> contains an element with
+        /// the specified key; otherwise, false.
+        /// </returns>
+        public bool TryGetMetaData<T>(string key, out T value)
+        {
+            if (this.metaData.TryGetValue(key, out object meta))
+            {
+                value = (T)meta;
+                return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+        /// <summary>
+        /// Clones this into a new instance
+        /// </summary>
+        /// <returns>The cloned metadata instance</returns>
+        public ImageMetaData Clone() => new ImageMetaData(this);
 
         /// <summary>
         /// Looks up a property with the provided name.
@@ -153,21 +200,9 @@ namespace SixLabors.ImageSharp.MetaData
             return false;
         }
 
-        /// <summary>
-        /// Clones this into a new instance
-        /// </summary>
-        /// <returns>The cloned metadata instance</returns>
-        public ImageMetaData Clone()
-        {
-            return new ImageMetaData(this);
-        }
-
         /// <summary>
         /// Synchronizes the profiles with the current meta data.
         /// </summary>
-        internal void SyncProfiles()
+        internal void SyncProfiles() => this.ExifProfile?.Sync(this);
-        {
-            this.ExifProfile?.Sync(this);
-        }
     }
 }

tests/ImageSharp.Tests/Formats/Gif/GifEncoderTests.cs

@@ -186,32 +186,37 @@ namespace SixLabors.ImageSharp.Tests.Formats.Gif
             using (var inStream = new MemoryStream(TestFile.Create(TestImages.Gif.Leo).Bytes))
             using (var outStream = new MemoryStream())
             {
-                var info = (GifInfo)Image.Identify(inStream);
-                GifColorTableMode colorMode = info.ColorTableMode;
                 inStream.Position = 0;
 
                 var image = Image.Load(inStream);
+                GifMetaData metaData = image.MetaData.GetGifMetaData();
+                GifFrameMetaData frameMetaData = image.Frames.RootFrame.MetaData.GetGifFrameMetaData();
+                GifColorTableMode colorMode = metaData.ColorTableMode;
                 var encoder = new GifEncoder()
                 {
                     ColorTableMode = colorMode,
-                    Quantizer = new OctreeQuantizer(image.Frames.RootFrame.MetaData.ColorTableLength)
+                    Quantizer = new OctreeQuantizer(frameMetaData.ColorTableLength)
                 };
 
                 image.Save(outStream, encoder);
                 outStream.Position = 0;
 
-                var cloneInfo = (GifInfo)Image.Identify(outStream);
                 outStream.Position = 0;
                 var clone = Image.Load(outStream);
 
+                GifMetaData cloneMetaData = clone.MetaData.GetGifMetaData();
+                Assert.Equal(metaData.ColorTableMode, cloneMetaData.ColorTableMode);
+
                 // Gifiddle and Cyotek GifInfo say this image has 64 colors.
-                Assert.Equal(64, image.Frames.RootFrame.MetaData.ColorTableLength);
+                Assert.Equal(64, frameMetaData.ColorTableLength);
-                Assert.Equal(info.ColorTableMode, cloneInfo.ColorTableMode);
 
                 for (int i = 0; i < image.Frames.Count; i++)
                 {
-                    Assert.Equal(image.Frames[i].MetaData.ColorTableLength, clone.Frames[i].MetaData.ColorTableLength);
+                    GifFrameMetaData ifm = image.Frames[i].MetaData.GetGifFrameMetaData();
-                    Assert.Equal(image.Frames[i].MetaData.FrameDelay, clone.Frames[i].MetaData.FrameDelay);
+                    GifFrameMetaData cifm = clone.Frames[i].MetaData.GetGifFrameMetaData();
+
+                    Assert.Equal(ifm.ColorTableLength, cifm.ColorTableLength);
+                    Assert.Equal(ifm.FrameDelay, cifm.FrameDelay);
                 }
 
                 image.Dispose();

tests/ImageSharp.Tests/Formats/Gif/Sections/GifGraphicControlExtensionTests.cs

@@ -12,10 +12,10 @@ namespace SixLabors.ImageSharp.Tests.Formats.Gif
         [Fact]
         public void TestPackedValue()
         {
-            Assert.Equal(0, GifGraphicControlExtension.GetPackedValue(DisposalMethod.Unspecified, false, false));
+            Assert.Equal(0, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.Unspecified, false, false));
-            Assert.Equal(11, GifGraphicControlExtension.GetPackedValue(DisposalMethod.RestoreToBackground, true, true));
+            Assert.Equal(11, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.RestoreToBackground, true, true));
-            Assert.Equal(4, GifGraphicControlExtension.GetPackedValue(DisposalMethod.NotDispose, false, false));
+            Assert.Equal(4, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.NotDispose, false, false));
-            Assert.Equal(14, GifGraphicControlExtension.GetPackedValue(DisposalMethod.RestoreToPrevious, true, false));
+            Assert.Equal(14, GifGraphicControlExtension.GetPackedValue(GifDisposalMethod.RestoreToPrevious, true, false));
         }
     }
 }

tests/ImageSharp.Tests/ImageInfoTests.cs

@@ -2,10 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using SixLabors.ImageSharp.Formats;
-using SixLabors.ImageSharp.Formats.Bmp;
-using SixLabors.ImageSharp.Formats.Gif;
-using SixLabors.ImageSharp.Formats.Jpeg;
-using SixLabors.ImageSharp.Formats.Png;
 using SixLabors.ImageSharp.MetaData;
 using SixLabors.Primitives;
 
@@ -16,7 +12,7 @@ namespace SixLabors.ImageSharp.Tests
     public class ImageInfoTests
     {
         [Fact]
-        public void JpegInfoInitializesCorrectly()
+        public void ImageInfoInitializesCorrectly()
         {
             const int Width = 50;
             const int Height = 60;
@@ -25,7 +21,7 @@ namespace SixLabors.ImageSharp.Tests
             var pixelType = new PixelTypeInfo(8);
             var meta = new ImageMetaData();
 
-            var info = new JpegInfo(pixelType, size, meta);
+            var info = new ImageInfo(pixelType, Width, Height, meta);
 
             Assert.Equal(pixelType, info.PixelType);
             Assert.Equal(Width, info.Width);
@@ -34,67 +30,5 @@ namespace SixLabors.ImageSharp.Tests
             Assert.Equal(rectangle, info.Bounds());
             Assert.Equal(meta, info.MetaData);
         }
-
-        [Fact]
-        public void BmpInfoInitializesCorrectly()
-        {
-            const int Width = 50;
-            const int Height = 60;
-            var size = new Size(Width, Height);
-            var rectangle = new Rectangle(0, 0, Width, Height);
-            var pixelType = new PixelTypeInfo(8);
-            var meta = new ImageMetaData();
-
-            var info = new BmpInfo(pixelType, size, meta);
-
-            Assert.Equal(pixelType, info.PixelType);
-            Assert.Equal(Width, info.Width);
-            Assert.Equal(Height, info.Height);
-            Assert.Equal(size, info.Size());
-            Assert.Equal(rectangle, info.Bounds());
-            Assert.Equal(meta, info.MetaData);
-        }
-
-        [Fact]
-        public void PngInfoInitializesCorrectly()
-        {
-            const int Width = 50;
-            const int Height = 60;
-            var size = new Size(Width, Height);
-            var rectangle = new Rectangle(0, 0, Width, Height);
-            var pixelType = new PixelTypeInfo(8);
-            var meta = new ImageMetaData();
-
-            var info = new PngInfo(pixelType, size, meta);
-
-            Assert.Equal(pixelType, info.PixelType);
-            Assert.Equal(Width, info.Width);
-            Assert.Equal(Height, info.Height);
-            Assert.Equal(size, info.Size());
-            Assert.Equal(rectangle, info.Bounds());
-            Assert.Equal(meta, info.MetaData);
-        }
-
-        [Fact]
-        public void GifInfoInitializesCorrectly()
-        {
-            const GifColorTableMode mode = GifColorTableMode.Local;
-            const int Width = 50;
-            const int Height = 60;
-            var size = new Size(Width, Height);
-            var rectangle = new Rectangle(0, 0, Width, Height);
-            var pixelType = new PixelTypeInfo(8);
-            var meta = new ImageMetaData();
-
-            var info = new GifInfo(mode, pixelType, size, meta);
-
-            Assert.Equal(mode, info.ColorTableMode);
-            Assert.Equal(pixelType, info.PixelType);
-            Assert.Equal(Width, info.Width);
-            Assert.Equal(Height, info.Height);
-            Assert.Equal(size, info.Size());
-            Assert.Equal(rectangle, info.Bounds());
-            Assert.Equal(meta, info.MetaData);
-        }
     }
 }

tests/ImageSharp.Tests/MetaData/ImageFrameMetaDataTests.cs

@@ -17,20 +17,24 @@ namespace SixLabors.ImageSharp.Tests
         {
             const int frameDelay = 42;
             const int colorTableLength = 128;
-            const DisposalMethod disposalMethod = DisposalMethod.RestoreToBackground;
+            const GifDisposalMethod disposalMethod = GifDisposalMethod.RestoreToBackground;
 
-            var metaData = new ImageFrameMetaData
+            var gifFrameMetaData = new GifFrameMetaData
             {
                 FrameDelay = frameDelay,
                 ColorTableLength = colorTableLength,
                 DisposalMethod = disposalMethod
             };
 
+            var metaData = new ImageFrameMetaData();
+            metaData.AddOrUpdateGifFrameMetaData(gifFrameMetaData);
+
             var clone = new ImageFrameMetaData(metaData);
+            GifFrameMetaData cloneGifFrameMetaData = clone.GetGifFrameMetaData();
 
-            Assert.Equal(frameDelay, clone.FrameDelay);
+            Assert.Equal(frameDelay, cloneGifFrameMetaData.FrameDelay);
-            Assert.Equal(colorTableLength, clone.ColorTableLength);
+            Assert.Equal(colorTableLength, cloneGifFrameMetaData.ColorTableLength);
-            Assert.Equal(disposalMethod, clone.DisposalMethod);
+            Assert.Equal(disposalMethod, cloneGifFrameMetaData.DisposalMethod);
         }
     }
 }

tests/ImageSharp.Tests/MetaData/ImageMetaDataTests.cs

@@ -28,7 +28,6 @@ namespace SixLabors.ImageSharp.Tests
             metaData.HorizontalResolution = 4;
             metaData.VerticalResolution = 2;
             metaData.Properties.Add(imageProperty);
-            metaData.RepeatCount = 1;
 
             ImageMetaData clone = metaData.Clone();
 
@@ -36,7 +35,6 @@ namespace SixLabors.ImageSharp.Tests
             Assert.Equal(4, clone.HorizontalResolution);
             Assert.Equal(2, clone.VerticalResolution);
             Assert.Equal(imageProperty, clone.Properties[0]);
-            Assert.Equal(1, clone.RepeatCount);
         }
 
         [Fact]

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/SystemDrawingReferenceDecoder.cs

@@ -48,16 +48,7 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs
             using (var sourceBitmap = new System.Drawing.Bitmap(stream))
             {
                 var pixelType = new PixelTypeInfo(System.Drawing.Image.GetPixelFormatSize(sourceBitmap.PixelFormat));
-                var size = new SixLabors.Primitives.Size(sourceBitmap.Width, sourceBitmap.Height);
+                return new ImageInfo(pixelType, sourceBitmap.Width, sourceBitmap.Height, new ImageMetaData());
-                return new SystemDrawingInfo(pixelType, size, new ImageMetaData());
-            }
-        }
-
-        private class SystemDrawingInfo : ImageInfo
-        {
-            public SystemDrawingInfo(PixelTypeInfo pixelType, SixLabors.Primitives.Size size, ImageMetaData metaData)
-                : base(pixelType, size, metaData)
-            {
             }
         }
     }