diff --git a/src/ImageSharp/Processing/ColorMatrix/Opacity.cs b/src/ImageSharp/Processing/ColorMatrix/Opacity.cs
index b310b4b915..b59c068905 100644
--- a/src/ImageSharp/Processing/ColorMatrix/Opacity.cs
+++ b/src/ImageSharp/Processing/ColorMatrix/Opacity.cs
@@ -14,7 +14,7 @@ namespace SixLabors.ImageSharp
     public static partial class ImageExtensions
     {
         /// <summary>
-        /// Alters the alpha component of the image.
+        /// Multiplies the alpha component of the image.
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The image this method extends.</param>
@@ -25,7 +25,7 @@ namespace SixLabors.ImageSharp
         => source.ApplyProcessor(new OpacityProcessor<TPixel>(amount));
 
         /// <summary>
-        /// Alters the alpha component of the image.
+        /// Multiplies the alpha component of the image.
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="source">The image this method extends.</param>
diff --git a/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs b/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs
index b1eea79d80..362df2be68 100644
--- a/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs
@@ -51,13 +51,15 @@ namespace SixLabors.ImageSharp.Tests
             TestBmpEncoderCore(provider, bitsPerPixel);
         }
 
+        
+
         private static void TestBmpEncoderCore<TPixel>(TestImageProvider<TPixel> provider, BmpBitsPerPixel bitsPerPixel)
             where TPixel : struct, IPixel<TPixel>
-        {
+        {   
             using (Image<TPixel> image = provider.GetImage())
             {
                 // there is no alpha in bmp!
-                image.Mutate(c => c.Opacity(1));
+                image.Mutate(c => c.MakeOpaque());
 
                 var encoder = new BmpEncoder { BitsPerPixel = bitsPerPixel };
 
diff --git a/tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.cs b/tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.cs
index 8610356b56..10657ea78f 100644
--- a/tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.cs
@@ -80,7 +80,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
             using (Image<TPixel> image = provider.GetImage())
             {
                 // There is no alpha in Jpeg!
-                image.Mutate(c => c.Opacity(1));
+                image.Mutate(c => c.MakeOpaque());
 
                 var encoder = new JpegEncoder()
                                   {
diff --git a/tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.cs b/tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.cs
index 28f156279c..c4f9b0debb 100644
--- a/tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.cs
@@ -123,26 +123,27 @@ namespace SixLabors.ImageSharp.Tests
             {
                 if (!HasAlpha(pngColorType))
                 {
-                    image.Mutate(c => c.Opacity(1));
+                    image.Mutate(c => c.MakeOpaque());
                 }
 
                 var encoder = new PngEncoder { PngColorType = pngColorType, CompressionLevel = compressionLevel};
 
-                string pngColorTypeInfo = appendPixelType ? pngColorType.ToString() : "";
+                string pngColorTypeInfo = appendPngColorType ? pngColorType.ToString() : "";
                 string compressionLevelInfo = appendCompressionLevel ? $"_C{compressionLevel}" : "";
                 string debugInfo = $"{pngColorTypeInfo}{compressionLevelInfo}";
-                string referenceInfo = $"{pngColorTypeInfo}";
-
+                
                 // Does DebugSave & load reference CompareToReferenceInput():
-                string path = ((ITestImageProvider)provider).Utility.SaveTestOutputFile(image, "png", encoder, debugInfo, appendPixelType);
+                string actualOutputFile = ((ITestImageProvider)provider).Utility.SaveTestOutputFile(image, "png", encoder, debugInfo, appendPixelType);
             
-                IImageDecoder referenceDecoder = TestEnvironment.GetReferenceDecoder(path);
-                string referenceOutputFile = ((ITestImageProvider)provider).Utility.GetReferenceOutputFileName("png", referenceInfo, appendPixelType);
+                IImageDecoder referenceDecoder = TestEnvironment.GetReferenceDecoder(actualOutputFile);
             
-                using (var encodedImage = Image.Load<TPixel>(referenceOutputFile, referenceDecoder))
+                using (var actualImage = Image.Load<TPixel>(actualOutputFile, referenceDecoder))
                 {
-                    ImageComparer comparer = pngColorType== PngColorType.Palette ? ImageComparer.Tolerant(ToleranceThresholdForPaletteEncoder) : ImageComparer.Exact;
-                    comparer.CompareImagesOrFrames(image, encodedImage);
+                    ImageComparer comparer = pngColorType == PngColorType.Palette
+                                                 ? ImageComparer.Tolerant(ToleranceThresholdForPaletteEncoder)
+                                                 : ImageComparer.Exact;
+
+                    comparer.VerifySimilarity(image, actualImage);
                 }
             }
         }
diff --git a/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs b/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
index 33dbc911e4..6f15cf439e 100644
--- a/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs
@@ -22,6 +22,38 @@ namespace SixLabors.ImageSharp.Tests
 
     public static class TestImageExtensions
     {
+        /// <summary>
+        /// TODO: This should be a common processing method! The image.Opacity(val) multiplies the alpha channel!
+        /// </summary>
+        /// <typeparam name="TPixel"></typeparam>
+        /// <param name="ctx"></param>
+        public static void MakeOpaque<TPixel>(this IImageProcessingContext<TPixel> ctx)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            ctx.Apply(
+                img =>
+                    {
+                        using (var temp = new Buffer2D<Vector4>(img.Width, img.Height))
+                        {
+                            Span<Vector4> tempSpan = temp.Span;
+                            foreach (ImageFrame<TPixel> frame in img.Frames)
+                            {
+                                Span<TPixel> pixelSpan = frame.GetPixelSpan();
+
+                                PixelOperations<TPixel>.Instance.ToVector4(pixelSpan, tempSpan, pixelSpan.Length);
+
+                                for (int i = 0; i < tempSpan.Length; i++)
+                                {
+                                    ref Vector4 v = ref tempSpan[i];
+                                    v.W = 1.0f;
+                                }
+
+                                PixelOperations<TPixel>.Instance.PackFromVector4(tempSpan, pixelSpan, pixelSpan.Length);
+                            }
+                        }
+                    });
+        }
+
         /// <summary>
         /// Saves the image only when not running in the CI server.
         /// </summary>
@@ -357,18 +389,13 @@ namespace SixLabors.ImageSharp.Tests
                                                    )
             where TPixel : struct, IPixel<TPixel>
         {
+            string actualOutputFile = provider.Utility.SaveTestOutputFile(image, extension, encoder, testOutputDetails, appendPixelTypeToFileName);
+            IImageDecoder referenceDecoder = TestEnvironment.GetReferenceDecoder(actualOutputFile);
 
-            provider.Utility.SaveTestOutputFile(image, extension, encoder, testOutputDetails, appendPixelTypeToFileName);
-            
-            referenceImageExtension = referenceImageExtension ?? extension;
-            string referenceOutputFile = provider.Utility.GetReferenceOutputFileName(referenceImageExtension, testOutputDetails, appendPixelTypeToFileName);
-
-            IImageDecoder referenceDecoder = TestEnvironment.GetReferenceDecoder(referenceOutputFile);
-
-            using (var encodedImage = Image.Load<TPixel>(referenceOutputFile, referenceDecoder))
+            using (var actualImage = Image.Load<TPixel>(actualOutputFile, referenceDecoder))
             {
                 ImageComparer comparer = customComparer ?? ImageComparer.Exact;
-                comparer.CompareImagesOrFrames(image, encodedImage);
+                comparer.VerifySimilarity(actualImage, image);
             }
         }
 
diff --git a/tests/ImageSharp.Tests/TestUtilities/Tests/ReferenceCodecTests.cs b/tests/ImageSharp.Tests/TestUtilities/Tests/ReferenceCodecTests.cs
index dde34fcc43..c67e4e06bf 100644
--- a/tests/ImageSharp.Tests/TestUtilities/Tests/ReferenceCodecTests.cs
+++ b/tests/ImageSharp.Tests/TestUtilities/Tests/ReferenceCodecTests.cs
@@ -56,7 +56,7 @@ namespace SixLabors.ImageSharp.Tests
             {
                 if (pngColorType != PngColorType.RgbWithAlpha)
                 {
-                    sourceImage.Mutate(c => c.Opacity(1));
+                    sourceImage.Mutate(c => c.MakeOpaque());
                 }
 
                 var encoder = new PngEncoder() { PngColorType = pngColorType };
@@ -93,12 +93,12 @@ namespace SixLabors.ImageSharp.Tests
 
             using (Image<TPixel> original = provider.GetImage())
             {
-                original.Mutate(c => c.Opacity(1));
+                original.Mutate(c => c.MakeOpaque());
                 using (var sdBitmap = new System.Drawing.Bitmap(path))
                 {
                     using (Image<TPixel> resaved = SystemDrawingBridge.FromFromRgb24SystemDrawingBitmap<TPixel>(sdBitmap))
                     {
-                        resaved.Mutate(c => c.Opacity(1));
+                        resaved.Mutate(c => c.MakeOpaque());
                         ImageComparer comparer = ImageComparer.Exact;
                         comparer.VerifySimilarity(original, resaved);
                     }