Nextfixes

src/ImageSharp/Formats/ImageFormatManager.cs

@@ -82,13 +82,10 @@ public class ImageFormatManager
         Guard.NotNull(format.FileExtensions, nameof(format.FileExtensions));
 
         lock (HashLock)
-        {
-            if (!this.imageFormats.Contains(format))
         {
             this.imageFormats.Add(format);
         }
     }
-    }
 
     /// <summary>
     /// For the specified file extensions type find the e <see cref="IImageFormat"/>.

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -1938,8 +1938,7 @@ internal sealed class PngDecoderCore : IImageDecoderInternals
         // Keywords should not be empty or have leading or trailing whitespace.
         name = PngConstants.Encoding.GetString(keywordBytes);
         return !string.IsNullOrWhiteSpace(name)
-            && !name.StartsWith(" ", StringComparison.Ordinal)
+            && !name.StartsWith(' ') && !name.EndsWith(' ');
-            && !name.EndsWith(" ", StringComparison.Ordinal);
     }
 
     private static bool IsXmpTextData(ReadOnlySpan<byte> keywordBytes)