adding images to mp3 files post pages/thumbnails

[BamsTheSergal]

Is your feature request related to a problem? Please describe.
it seems there is no option to add a image to a mp3, this would be useful for adding album art.

Describe the solution you'd like
a option when uploading a mp3, it asks if a image is related to it and if none is added, it can either be denied or just allow upload anyways

Describe alternatives you've considered
after uploading mp3, add a image after