diff --git a/src/ImageSharp/Common/Helpers/Guard.cs b/src/ImageSharp/Common/Helpers/Guard.cs
index 95211ccda8..96cd094cd8 100644
--- a/src/ImageSharp/Common/Helpers/Guard.cs
+++ b/src/ImageSharp/Common/Helpers/Guard.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp;
@@ -17,13 +16,14 @@ internal static partial class Guard
     /// <typeparam name="TValue">The type of the value.</typeparam>
     /// <exception cref="ArgumentException"><paramref name="value"/> is not a value type.</exception>
     [MethodImpl(InliningOptions.ShortMethod)]
-    public static void MustBeValueType<TValue>(TValue value, string parameterName)
+    public static void MustBeValueType<TValue>(TValue value, [CallerArgumentExpression("value")] string? parameterName = null)
+        where TValue : notnull
     {
         if (value.GetType().IsValueType)
         {
             return;
         }
 
-        ThrowHelper.ThrowArgumentException("Type must be a struct.", parameterName);
+        ThrowHelper.ThrowArgumentException("Type must be a struct.", parameterName!);
     }
 }
diff --git a/src/ImageSharp/ImageExtensions.cs b/src/ImageSharp/ImageExtensions.cs
index 04930a2689..cf970b3166 100644
--- a/src/ImageSharp/ImageExtensions.cs
+++ b/src/ImageSharp/ImageExtensions.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Globalization;
 using System.Text;
@@ -180,6 +179,6 @@ public static partial class ImageExtensions
 
         // Always available.
         stream.TryGetBuffer(out ArraySegment<byte> buffer);
-        return $"data:{format.DefaultMimeType};base64,{Convert.ToBase64String(buffer.Array, 0, (int)stream.Length)}";
+        return $"data:{format.DefaultMimeType};base64,{Convert.ToBase64String(buffer.Array ?? Array.Empty<byte>(), 0, (int)stream.Length)}";
     }
 }
diff --git a/src/ImageSharp/ImageFrame{TPixel}.cs b/src/ImageSharp/ImageFrame{TPixel}.cs
index fb4ee6ae5f..3734402d30 100644
--- a/src/ImageSharp/ImageFrame{TPixel}.cs
+++ b/src/ImageSharp/ImageFrame{TPixel}.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -145,7 +144,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     }
 
     /// <inheritdoc/>
-    public Buffer2D<TPixel> PixelBuffer { get; private set; }
+    public Buffer2D<TPixel> PixelBuffer { get; }
 
     /// <summary>
     /// Gets or sets the pixel at the specified position.
@@ -183,7 +182,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
 
         try
         {
-            var accessor = new PixelAccessor<TPixel>(this.PixelBuffer);
+            PixelAccessor<TPixel> accessor = new(this.PixelBuffer);
             processPixels(accessor);
         }
         finally
@@ -211,8 +210,8 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
 
         try
         {
-            var accessor1 = new PixelAccessor<TPixel>(this.PixelBuffer);
-            var accessor2 = new PixelAccessor<TPixel2>(frame2.PixelBuffer);
+            PixelAccessor<TPixel> accessor1 = new(this.PixelBuffer);
+            PixelAccessor<TPixel2> accessor2 = new(frame2.PixelBuffer);
             processPixels(accessor1, accessor2);
         }
         finally
@@ -247,9 +246,9 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
 
         try
         {
-            var accessor1 = new PixelAccessor<TPixel>(this.PixelBuffer);
-            var accessor2 = new PixelAccessor<TPixel2>(frame2.PixelBuffer);
-            var accessor3 = new PixelAccessor<TPixel3>(frame3.PixelBuffer);
+            PixelAccessor<TPixel> accessor1 = new(this.PixelBuffer);
+            PixelAccessor<TPixel2> accessor2 = new(frame2.PixelBuffer);
+            PixelAccessor<TPixel3> accessor3 = new(frame3.PixelBuffer);
             processPixels(accessor1, accessor2, accessor3);
         }
         finally
@@ -310,6 +309,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     /// Copies the pixels to a <see cref="Buffer2D{TPixel}"/> of the same size.
     /// </summary>
     /// <param name="target">The target pixel buffer accessor.</param>
+    /// <exception cref="ArgumentException">ImageFrame{TPixel}.CopyTo(): target must be of the same size!</exception>
     internal void CopyTo(Buffer2D<TPixel> target)
     {
         if (this.Size() != target.Size())
@@ -342,8 +342,7 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
 
         if (disposing)
         {
-            this.PixelBuffer?.Dispose();
-            this.PixelBuffer = null;
+            this.PixelBuffer.Dispose();
         }
 
         this.isDisposed = true;
@@ -379,14 +378,14 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     /// </summary>
     /// <param name="configuration">The configuration providing initialization code which allows extending the library.</param>
     /// <returns>The <see cref="ImageFrame{TPixel}"/></returns>
-    internal ImageFrame<TPixel> Clone(Configuration configuration) => new ImageFrame<TPixel>(configuration, this);
+    internal ImageFrame<TPixel> Clone(Configuration configuration) => new(configuration, this);
 
     /// <summary>
     /// Returns a copy of the image frame in the given pixel format.
     /// </summary>
     /// <typeparam name="TPixel2">The pixel format.</typeparam>
     /// <returns>The <see cref="ImageFrame{TPixel2}"/></returns>
-    internal ImageFrame<TPixel2> CloneAs<TPixel2>()
+    internal ImageFrame<TPixel2>? CloneAs<TPixel2>()
         where TPixel2 : unmanaged, IPixel<TPixel2> => this.CloneAs<TPixel2>(this.GetConfiguration());
 
     /// <summary>
@@ -400,11 +399,11 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     {
         if (typeof(TPixel2) == typeof(TPixel))
         {
-            return this.Clone(configuration) as ImageFrame<TPixel2>;
+            return (this.Clone(configuration) as ImageFrame<TPixel2>)!;
         }
 
-        var target = new ImageFrame<TPixel2>(configuration, this.Width, this.Height, this.Metadata.DeepClone());
-        var operation = new RowIntervalOperation<TPixel2>(this.PixelBuffer, target.PixelBuffer, configuration);
+        ImageFrame<TPixel2> target = new(configuration, this.Width, this.Height, this.Metadata.DeepClone());
+        RowIntervalOperation<TPixel2> operation = new(this.PixelBuffer, target.PixelBuffer, configuration);
 
         ParallelRowIterator.IterateRowIntervals(
             configuration,
@@ -447,14 +446,12 @@ public sealed class ImageFrame<TPixel> : ImageFrame, IPixelSource<TPixel>
     }
 
     [MethodImpl(InliningOptions.ColdPath)]
-    private static void ThrowArgumentOutOfRangeException(string paramName)
-    {
-        throw new ArgumentOutOfRangeException(paramName);
-    }
+    private static void ThrowArgumentOutOfRangeException(string paramName) => throw new ArgumentOutOfRangeException(paramName);
 
     /// <summary>
     /// A <see langword="struct"/> implementing the clone logic for <see cref="ImageFrame{TPixel}"/>.
     /// </summary>
+    /// <typeparam name="TPixel2">The type of the target pixel format.</typeparam>
     private readonly struct RowIntervalOperation<TPixel2> : IRowIntervalOperation
         where TPixel2 : unmanaged, IPixel<TPixel2>
     {
diff --git a/src/ImageSharp/IndexedImageFrame{TPixel}.cs b/src/ImageSharp/IndexedImageFrame{TPixel}.cs
index 741b3219e0..6807e77ad2 100644
--- a/src/ImageSharp/IndexedImageFrame{TPixel}.cs
+++ b/src/ImageSharp/IndexedImageFrame{TPixel}.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Runtime.CompilerServices;
@@ -18,8 +17,8 @@ namespace SixLabors.ImageSharp;
 public sealed class IndexedImageFrame<TPixel> : IPixelSource, IDisposable
     where TPixel : unmanaged, IPixel<TPixel>
 {
-    private Buffer2D<byte> pixelBuffer;
-    private IMemoryOwner<TPixel> paletteOwner;
+    private readonly Buffer2D<byte> pixelBuffer;
+    private readonly IMemoryOwner<TPixel> paletteOwner;
     private bool isDisposed;
 
     /// <summary>
@@ -109,8 +108,6 @@ public sealed class IndexedImageFrame<TPixel> : IPixelSource, IDisposable
             this.isDisposed = true;
             this.pixelBuffer.Dispose();
             this.paletteOwner.Dispose();
-            this.pixelBuffer = null;
-            this.paletteOwner = null;
         }
     }
 }
diff --git a/src/ImageSharp/Memory/Buffer2D{T}.cs b/src/ImageSharp/Memory/Buffer2D{T}.cs
index 8d6465389f..1173e02e17 100644
--- a/src/ImageSharp/Memory/Buffer2D{T}.cs
+++ b/src/ImageSharp/Memory/Buffer2D{T}.cs
@@ -55,6 +55,8 @@ public sealed class Buffer2D<T> : IDisposable
     /// </remarks>
     internal MemoryGroup<T> FastMemoryGroup { get; private set; }
 
+    internal bool IsDisposed { get; private set; }
+
     /// <summary>
     /// Gets a reference to the element at the specified position.
     /// </summary>
@@ -79,7 +81,11 @@ public sealed class Buffer2D<T> : IDisposable
     /// <summary>
     /// Disposes the <see cref="Buffer2D{T}"/> instance
     /// </summary>
-    public void Dispose() => this.FastMemoryGroup.Dispose();
+    public void Dispose()
+    {
+        this.FastMemoryGroup.Dispose();
+        this.IsDisposed = true;
+    }
 
     /// <summary>
     /// Gets a <see cref="Span{T}"/> to the row 'y' beginning from the pixel at the first pixel on that row.
diff --git a/src/ImageSharp/Processing/Extensions/ProcessingExtensions.cs b/src/ImageSharp/Processing/Extensions/ProcessingExtensions.cs
index 575ce293ca..f830ddfd09 100644
--- a/src/ImageSharp/Processing/Extensions/ProcessingExtensions.cs
+++ b/src/ImageSharp/Processing/Extensions/ProcessingExtensions.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.PixelFormats;
@@ -157,9 +156,9 @@ public static partial class ProcessingExtensions
         Guard.NotNull(operation, nameof(operation));
         source.EnsureNotDisposed();
 
-        var visitor = new ProcessingVisitor(configuration, operation, false);
+        ProcessingVisitor visitor = new(configuration, operation, false);
         source.AcceptVisitor(visitor);
-        return visitor.ResultImage;
+        return visitor.GetResultImage();
     }
 
     /// <summary>
@@ -275,6 +274,8 @@ public static partial class ProcessingExtensions
 
         private readonly bool mutate;
 
+        private Image? resultImage;
+
         public ProcessingVisitor(Configuration configuration, Action<IImageProcessingContext> operation, bool mutate)
         {
             this.configuration = configuration;
@@ -282,7 +283,7 @@ public static partial class ProcessingExtensions
             this.mutate = mutate;
         }
 
-        public Image ResultImage { get; private set; }
+        public Image GetResultImage() => this.resultImage!;
 
         public void Visit<TPixel>(Image<TPixel> image)
             where TPixel : unmanaged, IPixel<TPixel>
@@ -291,7 +292,7 @@ public static partial class ProcessingExtensions
                 this.configuration.ImageOperationsProvider.CreateImageProcessingContext(this.configuration, image, this.mutate);
 
             this.operation(operationsRunner);
-            this.ResultImage = operationsRunner.GetResultImage();
+            this.resultImage = operationsRunner.GetResultImage();
         }
     }
 }
diff --git a/src/ImageSharp/Processing/Processors/Transforms/Linear/AffineTransformProcessor.cs b/src/ImageSharp/Processing/Processors/Transforms/Linear/AffineTransformProcessor.cs
index abb8beccdf..30c279e593 100644
--- a/src/ImageSharp/Processing/Processors/Transforms/Linear/AffineTransformProcessor.cs
+++ b/src/ImageSharp/Processing/Processors/Transforms/Linear/AffineTransformProcessor.cs
@@ -19,7 +19,7 @@ public class AffineTransformProcessor : CloningImageProcessor
     public AffineTransformProcessor(Matrix3x2 matrix, IResampler sampler, Size targetDimensions)
     {
         Guard.NotNull(sampler, nameof(sampler));
-        Guard.MustBeValueType(sampler, nameof(sampler));
+        Guard.MustBeValueType(sampler);
 
         if (TransformUtils.IsDegenerate(matrix))
         {
diff --git a/src/ImageSharp/Processing/Processors/Transforms/Linear/ProjectiveTransformProcessor.cs b/src/ImageSharp/Processing/Processors/Transforms/Linear/ProjectiveTransformProcessor.cs
index 9b0b979e69..9e9507b737 100644
--- a/src/ImageSharp/Processing/Processors/Transforms/Linear/ProjectiveTransformProcessor.cs
+++ b/src/ImageSharp/Processing/Processors/Transforms/Linear/ProjectiveTransformProcessor.cs
@@ -19,7 +19,7 @@ public sealed class ProjectiveTransformProcessor : CloningImageProcessor
     public ProjectiveTransformProcessor(Matrix4x4 matrix, IResampler sampler, Size targetDimensions)
     {
         Guard.NotNull(sampler, nameof(sampler));
-        Guard.MustBeValueType(sampler, nameof(sampler));
+        Guard.MustBeValueType(sampler);
 
         if (TransformUtils.IsDegenerate(matrix))
         {
diff --git a/src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor.cs b/src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor.cs
index b7651c03f3..719622a28f 100644
--- a/src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor.cs
+++ b/src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor.cs
@@ -17,7 +17,7 @@ public class ResizeProcessor : CloningImageProcessor
     {
         Guard.NotNull(options, nameof(options));
         Guard.NotNull(options.Sampler, nameof(options.Sampler));
-        Guard.MustBeValueType(options.Sampler, nameof(options.Sampler));
+        Guard.MustBeValueType(options.Sampler);
 
         (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(sourceSize, options);
 
diff --git a/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs b/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs
index 44d6d8e720..ad0888ad77 100644
--- a/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs
+++ b/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs
@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.Processing;
 /// </summary>
 public class ProjectiveTransformBuilder
 {
-    private readonly List<Func<Size, Matrix4x4>> matrixFactories = new List<Func<Size, Matrix4x4>>();
+    private readonly List<Func<Size, Matrix4x4>> matrixFactories = new();
 
     /// <summary>
     /// Prepends a matrix that performs a tapering projective transform.
@@ -313,7 +313,7 @@ public class ProjectiveTransformBuilder
         Guard.MustBeGreaterThan(sourceRectangle.Height, 0, nameof(sourceRectangle));
 
         // Translate the origin matrix to cater for source rectangle offsets.
-        var matrix = Matrix4x4.CreateTranslation(new Vector3(-sourceRectangle.Location, 0));
+        Matrix4x4 matrix = Matrix4x4.CreateTranslation(new Vector3(-sourceRectangle.Location, 0));
 
         Size size = sourceRectangle.Size;
 
diff --git a/tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs b/tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs
index fba19065b0..62d1ef4db9 100644
--- a/tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs
+++ b/tests/ImageSharp.Tests/Image/ImageFrameCollectionTests.Generic.cs
@@ -182,12 +182,12 @@ public abstract partial class ImageFrameCollectionTests
                 new[] { imageFrame1, imageFrame2 });
 
             IPixelSource<Rgba32>[] framesSnapShot = collection.OfType<IPixelSource<Rgba32>>().ToArray();
+
+            Assert.All(framesSnapShot, f => Assert.False(f.PixelBuffer.IsDisposed));
+
             collection.Dispose();
 
-            Assert.All(
-                framesSnapShot,
-                f => // The pixel source of the frame is null after its been disposed.
-                    Assert.Null(f.PixelBuffer));
+            Assert.All(framesSnapShot, f => Assert.True(f.PixelBuffer.IsDisposed));
         }
 
         [Theory]