Override PhotometricInterpretation to RGB only in case of YCbCr, for black and white it should stay as it is

src/ImageSharp/Formats/Tiff/TiffDecoderOptionsParser.cs

@@ -476,17 +476,20 @@ internal static class TiffDecoderOptionsParser
 
             case TiffCompression.OldJpeg:
             {
-                options.CompressionType = TiffDecoderCompressionType.OldJpeg;
-
-                // Note: Setting PhotometricInterpretation and color type to RGB here, since the jpeg decoder will handle the conversion of the pixel data.
-                options.PhotometricInterpretation = TiffPhotometricInterpretation.Rgb;
-                options.ColorType = TiffColorType.Rgb;
-
                 if (!options.OldJpegCompressionStartOfImageMarker.HasValue)
                 {
                     TiffThrowHelper.ThrowNotSupported("Missing SOI marker offset for tiff with old jpeg compression");
                 }
 
+                options.CompressionType = TiffDecoderCompressionType.OldJpeg;
+
+                if (options.PhotometricInterpretation is TiffPhotometricInterpretation.YCbCr)
+                {
+                    // Note: Setting PhotometricInterpretation and color type to RGB here, since the jpeg decoder will handle the conversion of the pixel data.
+                    options.PhotometricInterpretation = TiffPhotometricInterpretation.Rgb;
+                    options.ColorType = TiffColorType.Rgb;
+                }
+
                 break;
             }