Fix args and add tests

src/ImageSharp/Formats/Jpeg/Components/Decoder/ComponentProcessors/ComponentProcessor.cs

@@ -16,7 +16,7 @@ internal abstract class ComponentProcessor : IDisposable
         this.Component = component;
 
         this.BlockAreaSize = component.SubSamplingDivisors * blockSize;
-        this.ColorBuffer = memoryAllocator.Allocate2DOveraligned<float>(
+        this.ColorBuffer = memoryAllocator.Allocate2DOverAligned<float>(
             postProcessorBufferSize.Width,
             postProcessorBufferSize.Height,
             this.BlockAreaSize.Height);

src/ImageSharp/Formats/Jpeg/Components/Encoder/ComponentProcessor.cs

@@ -28,7 +28,7 @@ internal class ComponentProcessor : IDisposable
         this.blockAreaSize = component.SubSamplingDivisors * 8;
 
         // alignment of 8 so each block stride can be sampled from a single 'ref pointer'
-        this.ColorBuffer = memoryAllocator.Allocate2DOveraligned<float>(
+        this.ColorBuffer = memoryAllocator.Allocate2DOverAligned<float>(
             postProcessorBufferSize.Width,
             postProcessorBufferSize.Height,
             8,

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -1968,6 +1968,9 @@ internal sealed class PngDecoderCore : IImageDecoderInternals
         }
 
         // We rent the buffer here to return it afterwards in Decode()
+        // We don't want to throw a degenerated memory exception here as we want to allow partial decoding
+        // so limit the length.
+        length = (int)Math.Min(length, this.currentStream.Length - this.currentStream.Position);
         IMemoryOwner<byte> buffer = this.configuration.MemoryAllocator.Allocate<byte>(length, AllocationOptions.Clean);
 
         this.currentStream.Read(buffer.GetSpan(), 0, length);

src/ImageSharp/Formats/Tga/TgaDecoderCore.cs

@@ -84,7 +84,7 @@ internal sealed class TgaDecoderCore : IImageDecoderInternals
                 throw new UnknownImageFormatException("Width or height cannot be 0");
             }
 
-            Image<TPixel> image = Image.CreateUninitialized<TPixel>(this.configuration, this.fileHeader.Width, this.fileHeader.Height, this.metadata);
+            Image<TPixel> image = new(this.configuration, this.fileHeader.Width, this.fileHeader.Height, this.metadata);
             Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
 
             if (this.fileHeader.ColorMapType == 1)

src/ImageSharp/Memory/Allocators/MemoryAllocator.cs

@@ -2,7 +2,6 @@
 // Licensed under the Six Labors Split License.
 
 using System.Buffers;
-using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Memory;
@@ -24,9 +23,7 @@ public abstract class MemoryAllocator
     /// </summary>
     public static MemoryAllocator Default { get; } = Create();
 
-    internal long MemoryGroupAllocationLimitBytes { get; private set; } = Environment.Is64BitProcess ?
-        4L * OneGigabyte :
-        OneGigabyte;
+    internal long MemoryGroupAllocationLimitBytes { get; private set; } = Environment.Is64BitProcess ? 4L * OneGigabyte : OneGigabyte;
 
     internal int SingleBufferAllocationLimitBytes { get; private set; } = OneGigabyte;
 
@@ -82,6 +79,7 @@ public abstract class MemoryAllocator
     /// <summary>
     /// Allocates a <see cref="MemoryGroup{T}"/>.
     /// </summary>
+    /// <typeparam name="T">The type of element to allocate.</typeparam>
     /// <param name="totalLength">The total length of the buffer.</param>
     /// <param name="bufferAlignment">The expected alignment (eg. to make sure image rows fit into single buffers).</param>
     /// <param name="options">The <see cref="AllocationOptions"/>.</param>
@@ -93,22 +91,19 @@ public abstract class MemoryAllocator
         AllocationOptions options = AllocationOptions.None)
         where T : struct
     {
-        long totalLengthInBytes = totalLength * Unsafe.SizeOf<T>();
-        if (totalLengthInBytes < 0)
+        if (totalLength < 0)
         {
-            ThrowNotRepresentable();
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(totalLength);
         }
 
-        if (totalLengthInBytes > this.MemoryGroupAllocationLimitBytes)
+        ulong totalLengthInBytes = (ulong)totalLength * (ulong)Unsafe.SizeOf<T>();
+        if (totalLengthInBytes > (ulong)this.MemoryGroupAllocationLimitBytes)
         {
             InvalidMemoryOperationException.ThrowAllocationOverLimitException(totalLengthInBytes, this.MemoryGroupAllocationLimitBytes);
         }
 
-        return this.AllocateGroupCore<T>(totalLengthInBytes, totalLength, bufferAlignment, options);
-
-        [DoesNotReturn]
-        static void ThrowNotRepresentable() =>
-            throw new InvalidMemoryOperationException("Attempted to allocate a MemoryGroup of a size that is not representable.");
+        // Cast to long is safe because we already checked that the total length is within the limit.
+        return this.AllocateGroupCore<T>(totalLength, (long)totalLengthInBytes, bufferAlignment, options);
     }
 
     internal virtual MemoryGroup<T> AllocateGroupCore<T>(long totalLengthInElements, long totalLengthInBytes, int bufferAlignment, AllocationOptions options)

src/ImageSharp/Memory/Allocators/MemoryAllocatorOptions.cs

@@ -17,7 +17,7 @@ public struct MemoryAllocatorOptions
     /// </summary>
     public int? MaximumPoolSizeMegabytes
     {
-        get => this.maximumPoolSizeMegabytes;
+        readonly get => this.maximumPoolSizeMegabytes;
         set
         {
             if (value.HasValue)
@@ -35,7 +35,7 @@ public struct MemoryAllocatorOptions
     /// </summary>
     public int? AllocationLimitMegabytes
     {
-        get => this.allocationLimitMegabytes;
+        readonly get => this.allocationLimitMegabytes;
         set
         {
             if (value.HasValue)

src/ImageSharp/Memory/Allocators/SimpleGcMemoryAllocator.cs

@@ -18,11 +18,13 @@ public sealed class SimpleGcMemoryAllocator : MemoryAllocator
     /// <inheritdoc />
     public override IMemoryOwner<T> Allocate<T>(int length, AllocationOptions options = AllocationOptions.None)
     {
-        Guard.MustBeGreaterThanOrEqualTo(length, 0, nameof(length));
-
-        int lengthInBytes = length * Unsafe.SizeOf<T>();
+        if (length < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(length);
+        }
 
-        if (lengthInBytes > this.SingleBufferAllocationLimitBytes)
+        ulong lengthInBytes = (ulong)length * (ulong)Unsafe.SizeOf<T>();
+        if (lengthInBytes > (ulong)this.SingleBufferAllocationLimitBytes)
         {
             InvalidMemoryOperationException.ThrowAllocationOverLimitException(lengthInBytes, this.SingleBufferAllocationLimitBytes);
         }

src/ImageSharp/Memory/Allocators/UniformUnmanagedMemoryPoolMemoryAllocator.cs

@@ -2,7 +2,6 @@
 // Licensed under the Six Labors Split License.
 
 using System.Buffers;
-using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Memory.Internals;
 
@@ -84,15 +83,18 @@ internal sealed class UniformUnmanagedMemoryPoolMemoryAllocator : MemoryAllocato
         int length,
         AllocationOptions options = AllocationOptions.None)
     {
-        Guard.MustBeGreaterThanOrEqualTo(length, 0, nameof(length));
-        int lengthInBytes = length * Unsafe.SizeOf<T>();
+        if (length < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(length);
+        }
 
-        if (lengthInBytes > this.SingleBufferAllocationLimitBytes)
+        ulong lengthInBytes = (ulong)length * (ulong)Unsafe.SizeOf<T>();
+        if (lengthInBytes > (ulong)this.SingleBufferAllocationLimitBytes)
         {
             InvalidMemoryOperationException.ThrowAllocationOverLimitException(lengthInBytes, this.SingleBufferAllocationLimitBytes);
         }
 
-        if (lengthInBytes <= this.sharedArrayPoolThresholdInBytes)
+        if (lengthInBytes <= (ulong)this.sharedArrayPoolThresholdInBytes)
         {
             var buffer = new SharedArrayPoolBuffer<T>(length);
             if (options.Has(AllocationOptions.Clean))
@@ -103,7 +105,7 @@ internal sealed class UniformUnmanagedMemoryPoolMemoryAllocator : MemoryAllocato
             return buffer;
         }
 
-        if (lengthInBytes <= this.poolBufferSizeInBytes)
+        if (lengthInBytes <= (ulong)this.poolBufferSizeInBytes)
         {
             UnmanagedMemoryHandle mem = this.pool.Rent();
             if (mem.IsValid)

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroup{T}.cs

@@ -83,15 +83,16 @@ internal abstract partial class MemoryGroup<T> : IMemoryGroup<T>, IDisposable
     {
         int bufferCapacityInBytes = allocator.GetBufferCapacityInBytes();
         Guard.NotNull(allocator, nameof(allocator));
-        Guard.MustBeGreaterThanOrEqualTo(totalLengthInElements, 0, nameof(totalLengthInElements));
-        Guard.MustBeGreaterThanOrEqualTo(bufferAlignmentInElements, 0, nameof(bufferAlignmentInElements));
 
-        int blockCapacityInElements = bufferCapacityInBytes / ElementSize;
+        if (totalLengthInElements < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(totalLengthInElements);
+        }
 
-        if (bufferAlignmentInElements > blockCapacityInElements)
+        int blockCapacityInElements = bufferCapacityInBytes / ElementSize;
+        if (bufferAlignmentInElements < 0 || bufferAlignmentInElements > blockCapacityInElements)
         {
-            throw new InvalidMemoryOperationException(
-                $"The buffer capacity of the provided MemoryAllocator is insufficient for the requested buffer alignment: {bufferAlignmentInElements}.");
+            InvalidMemoryOperationException.ThrowInvalidAlignmentException(bufferAlignmentInElements);
         }
 
         if (totalLengthInElements == 0)

src/ImageSharp/Memory/InvalidMemoryOperationException.cs

@@ -28,6 +28,15 @@ public class InvalidMemoryOperationException : InvalidOperationException
     }
 
     [DoesNotReturn]
-    internal static void ThrowAllocationOverLimitException(long length, long limit) =>
+    internal static void ThrowNegativeAllocationException(long length) =>
+        throw new InvalidMemoryOperationException($"Attempted to allocate a buffer of negative length={length}.");
+
+    [DoesNotReturn]
+    internal static void ThrowInvalidAlignmentException(long alignment) =>
+        throw new InvalidMemoryOperationException(
+                $"The buffer capacity of the provided MemoryAllocator is insufficient for the requested buffer alignment: {alignment}.");
+
+    [DoesNotReturn]
+    internal static void ThrowAllocationOverLimitException(ulong length, long limit) =>
             throw new InvalidMemoryOperationException($"Attempted to allocate a buffer of length={length} that exceeded the limit {limit}.");
 }

src/ImageSharp/Memory/MemoryAllocatorExtensions.cs

@@ -18,20 +18,20 @@ public static class MemoryAllocatorExtensions
     /// <param name="memoryAllocator">The memory allocator.</param>
     /// <param name="width">The buffer width.</param>
     /// <param name="height">The buffer height.</param>
-    /// <param name="preferContiguosImageBuffers">A value indicating whether the allocated buffer should be contiguous, unless bigger than <see cref="int.MaxValue"/>.</param>
+    /// <param name="preferContiguousImageBuffers">A value indicating whether the allocated buffer should be contiguous, unless bigger than <see cref="int.MaxValue"/>.</param>
     /// <param name="options">The allocation options.</param>
     /// <returns>The <see cref="Buffer2D{T}"/>.</returns>
     public static Buffer2D<T> Allocate2D<T>(
         this MemoryAllocator memoryAllocator,
         int width,
         int height,
-        bool preferContiguosImageBuffers,
+        bool preferContiguousImageBuffers,
         AllocationOptions options = AllocationOptions.None)
         where T : struct
     {
         long groupLength = (long)width * height;
         MemoryGroup<T> memoryGroup;
-        if (preferContiguosImageBuffers && groupLength < int.MaxValue)
+        if (preferContiguousImageBuffers && groupLength < int.MaxValue)
         {
             IMemoryOwner<T> buffer = memoryAllocator.Allocate<T>((int)groupLength, options);
             memoryGroup = MemoryGroup<T>.CreateContiguous(buffer, false);
@@ -69,16 +69,16 @@ public static class MemoryAllocatorExtensions
     /// <typeparam name="T">The type of buffer items to allocate.</typeparam>
     /// <param name="memoryAllocator">The memory allocator.</param>
     /// <param name="size">The buffer size.</param>
-    /// <param name="preferContiguosImageBuffers">A value indicating whether the allocated buffer should be contiguous, unless bigger than <see cref="int.MaxValue"/>.</param>
+    /// <param name="preferContiguousImageBuffers">A value indicating whether the allocated buffer should be contiguous, unless bigger than <see cref="int.MaxValue"/>.</param>
     /// <param name="options">The allocation options.</param>
     /// <returns>The <see cref="Buffer2D{T}"/>.</returns>
     public static Buffer2D<T> Allocate2D<T>(
         this MemoryAllocator memoryAllocator,
         Size size,
-        bool preferContiguosImageBuffers,
+        bool preferContiguousImageBuffers,
         AllocationOptions options = AllocationOptions.None)
         where T : struct =>
-        Allocate2D<T>(memoryAllocator, size.Width, size.Height, preferContiguosImageBuffers, options);
+        Allocate2D<T>(memoryAllocator, size.Width, size.Height, preferContiguousImageBuffers, options);
 
     /// <summary>
     /// Allocates a buffer of value type objects interpreted as a 2D region
@@ -96,7 +96,7 @@ public static class MemoryAllocatorExtensions
         where T : struct =>
         Allocate2D<T>(memoryAllocator, size.Width, size.Height, false, options);
 
-    internal static Buffer2D<T> Allocate2DOveraligned<T>(
+    internal static Buffer2D<T> Allocate2DOverAligned<T>(
         this MemoryAllocator memoryAllocator,
         int width,
         int height,

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeKernelMap.cs

@@ -50,7 +50,7 @@ internal partial class ResizeKernelMap : IDisposable
         this.sourceLength = sourceLength;
         this.DestinationLength = destinationLength;
         this.MaxDiameter = (radius * 2) + 1;
-        this.data = memoryAllocator.Allocate2D<float>(this.MaxDiameter, bufferHeight, preferContiguosImageBuffers: true, AllocationOptions.Clean);
+        this.data = memoryAllocator.Allocate2D<float>(this.MaxDiameter, bufferHeight, preferContiguousImageBuffers: true, AllocationOptions.Clean);
         this.pinHandle = this.data.DangerousGetSingleMemory().Pin();
         this.kernels = new ResizeKernel[destinationLength];
         this.tempValues = new double[this.MaxDiameter];

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeWorker.cs

@@ -83,7 +83,7 @@ internal sealed class ResizeWorker<TPixel> : IDisposable
         this.transposedFirstPassBuffer = configuration.MemoryAllocator.Allocate2D<Vector4>(
             this.workerHeight,
             targetWorkingRect.Width,
-            preferContiguosImageBuffers: true,
+            preferContiguousImageBuffers: true,
             options: AllocationOptions.Clean);
 
         this.tempRowBuffer = configuration.MemoryAllocator.Allocate<Vector4>(this.sourceRectangle.Width);

tests/ImageSharp.Tests/Formats/Bmp/BmpDecoderTests.cs

@@ -558,4 +558,13 @@ public class BmpDecoderTests
         // Compare to reference output instead.
         image.CompareToReferenceOutput(provider, extension: "png");
     }
+
+    [Theory]
+    [WithFile(Issue2696, PixelTypes.Rgba32)]
+    public void BmpDecoder_ThrowsException_Issue2696<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+        => Assert.Throws<InvalidImageContentException>(() =>
+        {
+            using Image<TPixel> image = provider.GetImage(BmpDecoder.Instance);
+        });
 }

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs

@@ -338,21 +338,11 @@ public partial class JpegDecoderTests
     }
 
     [Theory]
-    [WithFile(TestImages.Jpeg.Issues.HangBadScan, PixelTypes.L8)]
-    public void DecodeHang<TPixel>(TestImageProvider<TPixel> provider)
+    [WithFile(TestImages.Jpeg.Issues.HangBadScan, PixelTypes.Rgb24)]
+    public void DecodeHang_ThrowsException<TPixel>(TestImageProvider<TPixel> provider)
         where TPixel : unmanaged, IPixel<TPixel>
-    {
-        if (TestEnvironment.IsWindows &&
-            TestEnvironment.RunsOnCI)
-        {
-            // Windows CI runs consistently fail with OOM.
-            return;
-        }
-
-        using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance);
-        Assert.Equal(65503, image.Width);
-        Assert.Equal(65503, image.Height);
-    }
+        => Assert.Throws<InvalidImageContentException>(
+            () => { using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance); });
 
     // https://github.com/SixLabors/ImageSharp/issues/2517
     [Theory]

tests/ImageSharp.Tests/Memory/Allocators/SimpleGcMemoryAllocatorTests.cs

@@ -19,13 +19,17 @@ public class SimpleGcMemoryAllocatorTests
 
     protected SimpleGcMemoryAllocator MemoryAllocator { get; } = new SimpleGcMemoryAllocator();
 
-    [Theory]
-    [InlineData(-1)]
-    public void Allocate_IncorrectAmount_ThrowsCorrect_ArgumentOutOfRangeException(int length)
+    public static TheoryData<int> InvalidLengths { get; set; } = new()
     {
-        ArgumentOutOfRangeException ex = Assert.Throws<ArgumentOutOfRangeException>(() => this.MemoryAllocator.Allocate<BigStruct>(length));
-        Assert.Equal("length", ex.ParamName);
-    }
+        { -1 },
+        { (1 << 30) + 1 }
+    };
+
+    [Theory]
+    [MemberData(nameof(InvalidLengths))]
+    public void Allocate_IncorrectAmount_ThrowsCorrect_InvalidMemoryOperationException(int length)
+        => Assert.Throws<InvalidMemoryOperationException>(
+            () => this.MemoryAllocator.Allocate<BigStruct>(length));
 
     [Fact]
     public unsafe void Allocate_MemoryIsPinnableMultipleTimes()

tests/ImageSharp.Tests/Memory/Allocators/UniformUnmanagedPoolMemoryAllocatorTests.cs

@@ -111,9 +111,20 @@ public class UniformUnmanagedPoolMemoryAllocatorTests
     public void AllocateGroup_SizeInBytesOverLongMaxValue_ThrowsInvalidMemoryOperationException()
     {
         var allocator = new UniformUnmanagedMemoryPoolMemoryAllocator(null);
-        Assert.Throws<InvalidMemoryOperationException>(() => allocator.AllocateGroup<S4>(int.MaxValue * (long)int.MaxValue, int.MaxValue));
+        Assert.Throws<InvalidMemoryOperationException>(() => allocator.AllocateGroup<byte>(int.MaxValue * (long)int.MaxValue, int.MaxValue));
     }
 
+    public static TheoryData<int> InvalidLengths { get; set; } = new()
+    {
+        { -1 },
+        { (1 << 30) + 1 }
+    };
+
+    [Theory]
+    [MemberData(nameof(InvalidLengths))]
+    public void Allocate_IncorrectAmount_ThrowsCorrect_InvalidMemoryOperationException(int length)
+        => Assert.Throws<InvalidMemoryOperationException>(() => new UniformUnmanagedMemoryPoolMemoryAllocator(null).Allocate<S512>(length));
+
     [Fact]
     public unsafe void Allocate_MemoryIsPinnableMultipleTimes()
     {

tests/ImageSharp.Tests/Memory/Buffer2DTests.cs

@@ -4,6 +4,7 @@
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.PixelFormats;
 
 // ReSharper disable InconsistentNaming
 namespace SixLabors.ImageSharp.Tests.Memory;
@@ -72,11 +73,11 @@ public partial class Buffer2DTests
         using Buffer2D<byte> buffer = useSizeOverload ?
             this.MemoryAllocator.Allocate2D<byte>(
                 new Size(200, 200),
-                preferContiguosImageBuffers: true) :
+                preferContiguousImageBuffers: true) :
             this.MemoryAllocator.Allocate2D<byte>(
             200,
             200,
-            preferContiguosImageBuffers: true);
+            preferContiguousImageBuffers: true);
         Assert.Equal(1, buffer.FastMemoryGroup.Count);
         Assert.Equal(200 * 200, buffer.FastMemoryGroup.TotalLength);
     }
@@ -87,7 +88,7 @@ public partial class Buffer2DTests
     {
         this.MemoryAllocator.BufferCapacityInBytes = sizeof(int) * bufferCapacity;
 
-        using Buffer2D<int> buffer = this.MemoryAllocator.Allocate2DOveraligned<int>(width, height, alignmentMultiplier);
+        using Buffer2D<int> buffer = this.MemoryAllocator.Allocate2DOverAligned<int>(width, height, alignmentMultiplier);
         MemoryGroup<int> memoryGroup = buffer.FastMemoryGroup;
         int expectedAlignment = width * alignmentMultiplier;
 
@@ -337,4 +338,26 @@ public partial class Buffer2DTests
         Assert.False(mgBefore.IsValid);
         Assert.NotSame(mgBefore, buffer1.MemoryGroup);
     }
+
+    public static TheoryData<Size> InvalidLengths { get; set; } = new()
+    {
+        { new(-1, -1) },
+        { new(32768, 32769) },
+        { new(32769, 32768) }
+    };
+
+    [Theory]
+    [MemberData(nameof(InvalidLengths))]
+    public void Allocate_IncorrectAmount_ThrowsCorrect_InvalidMemoryOperationException(Size size)
+        => Assert.Throws<InvalidMemoryOperationException>(() => this.MemoryAllocator.Allocate2D<Rgba32>(size.Width, size.Height));
+
+    [Theory]
+    [MemberData(nameof(InvalidLengths))]
+    public void Allocate_IncorrectAmount_ThrowsCorrect_InvalidMemoryOperationException_Size(Size size)
+        => Assert.Throws<InvalidMemoryOperationException>(() => this.MemoryAllocator.Allocate2D<Rgba32>(new Size(size)));
+
+    [Theory]
+    [MemberData(nameof(InvalidLengths))]
+    public void Allocate_IncorrectAmount_ThrowsCorrect_InvalidMemoryOperationException_OverAligned(Size size)
+        => Assert.Throws<InvalidMemoryOperationException>(() => this.MemoryAllocator.Allocate2DOverAligned<Rgba32>(size.Width, size.Height, 1));
 }

tests/ImageSharp.Tests/Memory/DiscontiguousBuffers/MemoryGroupTests.Allocate.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
 using System.Runtime.CompilerServices;
@@ -219,11 +219,17 @@ public partial class MemoryGroupTests
 [StructLayout(LayoutKind.Sequential, Size = 5)]
 internal struct S5
 {
-    public override string ToString() => "S5";
+    public override readonly string ToString() => nameof(S5);
 }
 
 [StructLayout(LayoutKind.Sequential, Size = 4)]
 internal struct S4
 {
-    public override string ToString() => "S4";
+    public override readonly string ToString() => nameof(S4);
+}
+
+[StructLayout(LayoutKind.Explicit, Size = 512)]
+internal struct S512
+{
+    public override readonly string ToString() => nameof(S512);
 }

tests/ImageSharp.Tests/TestImages.cs

@@ -439,6 +439,8 @@ public static class TestImages
         public const string Rgba321010102 = "Bmp/rgba32-1010102.bmp";
         public const string RgbaAlphaBitfields = "Bmp/rgba32abf.bmp";
 
+        public const string Issue2696 = "Bmp/issue-2696.bmp";
+
         public const string BlackWhitePalletDataMatrix = "Bmp/bit1datamatrix.bmp";
 
         public static readonly string[] BitFields =

tests/Images/Input/Bmp/issue-2696.bmp

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:de7e7ec0454a55f6a76c859f356b240a3d4cb56ca50dfa209a1813dd09e12076
+size 143