I installed Volumio and made it access by music library. I can access all my music, but there is no artist art. there is album art, as contained in the mp3 files, but on the artist level, there are only star-symbols for those artist Volumio seems to recognize, and people-icons for the other ones - see the screenshot:
artist list.png (107.64 KiB) Viewed 28 times
This is Volumio 2.575. I had seen artist art in earlier versions of Volumio, but do to new hardware I had installed from scratch, and can't seem to get the artist art back in that version.