I have noticed a new behaviour for several months now, where cover images drag+dropped from Firefox are imported as PNG instead of JPG. Dropping the same images from another browser imports the original JPG, but Firefox for some reason is dropping as PNG. I tested old versions of MP3tag and the same thing happens, and I know for a fact it didn’t used to, so it’s likely something to do with Firefox. However, drag+drop from Firefox to my desktop or a local folder saves a JPG, so I don’t know where the PNG is coming from.
I am not seeing that behavior. I am using Mp3tag 3.31c and the latest ESR version of Firefox. They all import as image/jpeg
What I did was: i clicked an Image on Google Image Search, clicked on the image and i then, on the image that appeared on the right hand side, drag and dropped that in the Mp3 file in Mp3tag and it showed as Image/jpeg
Well it looks like Mozilla has fixed whatever was causing it… I tested the version I was using and the latest version with a fresh profile and no addons: The latest version (143.0.1) drops JPG and the previous version drops PNG. It had been happening for months through previous Firefox updates in the past and the problem remained. It seems I should have tried updating once more before posting!