TLDR: If album art is not showing up for MP3s from BandCamp, use Kid3 to change the “text encoding” for the APIC id3 frame that holds the album art, from UTF-16 to ISO-8859-1.
I have an issue in Engine Prime (1.3.4) on macOS with album art not showing up for tracks purchased on BandCamp (tried multiple imports, “Re-import Track Information”, etc. to no avail). Here’s the workaround that worked for me, with technical details that I can see.
From BandCamp, I download tracks in “MP3 320” CBR format. I use Kid3 software to inspect/edit id3 tags. In freshly downloaded BandCamp MP3s, only id3v2.3.0 tags are present, and album art is there (and visible in other software, in Finder, etc.) in the APIC frame. However if you go to “edit” the picture tag, you can see that the frame’s “text encoding” is set to “UTF-16”. I think this confuses Engine Prime. After changing the “text encoding” of the APIC frame and saving the file, album art will successfully import in Engine Prime (both re-adding the track and the “re-import track information” option work).
Hopefully devs can fix this issue and read the APIC frame correctly!