Comment 5 for bug 1607531

You cannot drop an arbitrary jpg file into a music folder and expect it to be picked up as artwork. This simply doesn't work. The following file basenames are recognised cover art:

cover
album
albumart
.folder
folder

These base names must have one of the following extensions:

jpeg
jpg
png

Capitalisation is irrelevant. So, if you have a file called

AlbumArt.JPG

it will be used as the album cover.

If a song contains embedded artwork, it will be used. Otherwise, if one of these files is present, the contents of the file are used. Otherwise, we try to retrieve albumart from a database. The accuracy of the lookup depends on the accuracy of the tags in the song and whether the database (7digital) has a corresponding entry.

At any rate, there is no bug here. You can embed cover art in your songs, or use one of the filenames listed above if you don't want to do that.