Minor cleanup

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -337,9 +337,9 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
 
     /// <summary>
     /// Skips over a block or reads its terminator.
-    /// <param name="blockSize">The length of the block to skip.</param>
-    /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
     /// </summary>
+    /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
+    /// <param name="blockSize">The length of the block to skip.</param>
     private static void SkipBlock(BufferedReadStream stream, int blockSize = 0)
     {
         if (blockSize > 0)
@@ -363,7 +363,7 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
     {
         int length;
 
-        StringBuilder stringBuilder = new StringBuilder();
+        StringBuilder stringBuilder = new();
         while ((length = stream.ReadByte()) != 0)
         {
             if (length > GifConstants.MaxCommentSubBlockLength)
@@ -450,7 +450,7 @@ internal sealed class GifDecoderCore : IImageDecoderInternals
     private void ReadFrameIndices(BufferedReadStream stream, Buffer2D<byte> indices)
     {
         int minCodeSize = stream.ReadByte();
-        using LzwDecoder lzwDecoder = new LzwDecoder(this.configuration.MemoryAllocator, stream);
+        using LzwDecoder lzwDecoder = new(this.configuration.MemoryAllocator, stream);
         lzwDecoder.DecodePixels(minCodeSize, indices);
     }
 

src/ImageSharp/Formats/Gif/GifEncoderCore.cs

@@ -2,7 +2,6 @@
 // Licensed under the Six Labors Split License.
 
 using System.Buffers;
-using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.Advanced;
@@ -141,7 +140,7 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
     private void EncodeFrames<TPixel>(
         Stream stream,
         Image<TPixel> image,
-        IndexedImageFrame<TPixel>? quantized,
+        IndexedImageFrame<TPixel> quantized,
         ReadOnlyMemory<TPixel> palette)
         where TPixel : unmanaged, IPixel<TPixel>
     {
@@ -168,7 +167,6 @@ internal sealed class GifEncoderCore : IImageEncoderInternals
 
             // Clean up for the next run.
             quantized.Dispose();
-            quantized = null;
         }
 
         if (hasPaletteQuantizer)

src/ImageSharp/Image.cs

@@ -30,7 +30,7 @@ public abstract partial class Image : ImageInfo, IDisposable, IConfigurationProv
     /// <param name="size">The size in px units.</param>
     protected Image(Configuration configuration, PixelTypeInfo pixelType, ImageMetadata? metadata, Size size)
        : base(pixelType, size, metadata)
-        => this.configuration = configuration ?? Configuration.Default;
+        => this.configuration = configuration;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="Image"/> class.