Board Thread:Support Requests - Getting Technical/@comment-896291-20140625091619

Hey guys, every now and again, I try to upload a png image and this message: "File extension ".$1" does not match the detected MIME type of the file ($2)." but if I change the file to jpg, it disappears and allows the image to upload.

What exactly does this mean, but it has bugged me for the longest time. 