fix #277

src/ImageSharp/Formats/Bmp/BmpFormat.cs

@@ -8,7 +8,7 @@ namespace ImageSharp.Formats
     using System.Collections.Generic;
 
     /// <summary>
-    /// Registers the image encoders, decoders and mime type detectors for the jpeg format.
+    /// Registers the image encoders, decoders and mime type detectors for the bmp format.
     /// </summary>
     internal sealed class BmpFormat : IImageFormat
     {

src/ImageSharp/Formats/Gif/GifFormat.cs

@@ -8,7 +8,7 @@ namespace ImageSharp.Formats
     using System.Collections.Generic;
 
     /// <summary>
-    /// Registers the image encoders, decoders and mime type detectors for the jpeg format.
+    /// Registers the image encoders, decoders and mime type detectors for the gif format.
     /// </summary>
     internal sealed class GifFormat : IImageFormat
     {

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -825,14 +825,14 @@ namespace ImageSharp.Formats
                         using (var compressed = new Buffer<byte>(length))
                         {
                             // TODO: Should we use pack from vector here instead?
-                            this.From16BitTo8Bit(new Span<byte>(defilteredScanline), compressed, length);
+                            this.From16BitTo8Bit(new Span<byte>(defilteredScanline, 1), compressed, length);
-                            for (int x = pixelOffset, o = 1;
+                            for (int x = pixelOffset, o = 0;
                                  x < this.header.Width;
-                                 x += increment, o += this.bytesPerPixel)
+                                 x += increment, o += 3)
                             {
                                 rgba.R = compressed[o];
-                                rgba.G = compressed[o + this.bytesPerSample];
+                                rgba.G = compressed[o + 1];
-                                rgba.B = compressed[o + (2 * this.bytesPerSample)];
+                                rgba.B = compressed[o + 2];
 
                                 color.PackFromRgba32(rgba);
                                 rowSpan[x] = color;
@@ -862,13 +862,13 @@ namespace ImageSharp.Formats
                         using (var compressed = new Buffer<byte>(length))
                         {
                             // TODO: Should we use pack from vector here instead?
-                            this.From16BitTo8Bit(new Span<byte>(defilteredScanline), compressed, length);
+                            this.From16BitTo8Bit(new Span<byte>(defilteredScanline, 1), compressed, length);
-                            for (int x = pixelOffset, o = 1; x < this.header.Width; x += increment, o += this.bytesPerPixel)
+                            for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o += 4)
                             {
                                 rgba.R = compressed[o];
-                                rgba.G = compressed[o + this.bytesPerSample];
+                                rgba.G = compressed[o + 1];
-                                rgba.B = compressed[o + (2 * this.bytesPerSample)];
+                                rgba.B = compressed[o + 2];
-                                rgba.A = compressed[o + (3 * this.bytesPerSample)];
+                                rgba.A = compressed[o + 3];
 
                                 color.PackFromRgba32(rgba);
                                 rowSpan[x] = color;

src/ImageSharp/Formats/Png/PngFormat.cs

@@ -8,7 +8,7 @@ namespace ImageSharp.Formats
     using System.Collections.Generic;
 
     /// <summary>
-    /// Registers the image encoders, decoders and mime type detectors for the jpeg format.
+    /// Registers the image encoders, decoders and mime type detectors for the png format.
     /// </summary>
     internal sealed class PngFormat : IImageFormat
     {

tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs

@@ -18,7 +18,7 @@ namespace ImageSharp.Tests
         public static readonly string[] TestFiles =
             {
                 TestImages.Png.Splash, TestImages.Png.Indexed, TestImages.Png.Interlaced, TestImages.Png.FilterVar,
-                TestImages.Png.Bad.ChunkLength1, TestImages.Png.Bad.ChunkLength2, TestImages.Png.Rgb48Bpp
+                TestImages.Png.Bad.ChunkLength1, TestImages.Png.Bad.ChunkLength2, TestImages.Png.Rgb48Bpp, TestImages.Png.Rgb48BppInterlaced
             };
 
         [Theory]

tests/ImageSharp.Tests/TestImages.cs

@@ -26,6 +26,7 @@ namespace ImageSharp.Tests
             public const string SplashInterlaced = "Png/splash-interlaced.png";
             public const string Interlaced = "Png/interlaced.png";
             public const string Rgb48Bpp = "Png/rgb-48bpp.png";
+            public const string Rgb48BppInterlaced = "Png/rgb-48bpp-interlaced.png";
 
             // Filtered test images from http://www.schaik.com/pngsuite/pngsuite_fil_png.html
             public const string Filter0 = "Png/filter0.png";