Switched Preserve to be 0 for PngTransparentColorBehavior enum

src/ImageSharp/Formats/Png/PngChunkFilter.cs

@@ -1,5 +1,5 @@
 // Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
+// Licensed under the GNU Affero General Public License, Version 3.
 
 using System;
 

src/ImageSharp/Formats/Png/PngTransparentColorBehavior.cs

@@ -9,14 +9,14 @@ namespace SixLabors.ImageSharp.Formats.Png
     public enum PngTransparentColorBehavior
     {
         /// <summary>
-        /// Converts fully transparent pixels that may contain R, G, B values which are not 0,
-        /// to transparent black, which can yield in better compression in some cases.
+        /// The transparency will be kept as is.
         /// </summary>
-        Clear,
+        Preserve = 0,
 
         /// <summary>
-        /// The transparency will be kept as is.
+        /// Converts fully transparent pixels that may contain R, G, B values which are not 0,
+        /// to transparent black, which can yield in better compression in some cases.
         /// </summary>
-        Preserve
+        Clear = 1,
     }
 }

tests/ImageSharp.Tests/Formats/Png/PngEncoderTests.Chunks.cs

@@ -1,5 +1,5 @@
 // Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
+// Licensed under the GNU Affero General Public License, Version 3.
 
 using System;
 using System.Buffers.Binary;