fix embedded image resolving as video track

MediaBrowser.MediaEncoding/Probing/ProbeResultNormalizer.cs

@@ -129,7 +129,7 @@ namespace MediaBrowser.MediaEncoding.Probing
             }
             else if (string.Equals(streamInfo.codec_type, "video", StringComparison.OrdinalIgnoreCase))
             {
-                stream.Type = isAudio
+                stream.Type = isAudio || string.Equals(stream.Codec, "mjpeg", StringComparison.OrdinalIgnoreCase)
                     ? MediaStreamType.EmbeddedImage
                     : MediaStreamType.Video;