I use volumio 2.035 installed on a raspberry 3. I just installed the image and made no changes.
ON the inserted usb stick are several mp3 albums. The mp3 files have been edited using mp3tag. All mp3 files include a cover art.
When browsing the file with volumio or start to play them, not all covers are displayed. For some albums/mp3 files the cover art is displayed correctly for the other files a generic art cover is displayed (looks like a mixture of several cover pictures with an big o over it)