[pkscout]

I may have been fooled into thinking I was downloading Fanart.tv by my merely relying on filenaming conventions and file dimensions (there are many duplicate entries within theaudiodb).  I found an example (CAKE) where there were two images on fanart.tv not on theaudiodb, and adding the musicbrainz id to the artist AS grabbed these two missing images.

So another question: how do you handle musicbrainz_artistid numbers of the format #/# (e.g., Bonnie Davis - Don't Stop Now.mp3 = 7f8b1490-5490-4f60-8233-9972e1977aec/a05cebe9-3c27-4b79-8a33-db24a82c45ba/c0e2ac29-928e-4e50-a446-1634b602cd55)?

I don't handle any of that in the add-on.  The music scraper is the thing that figures all that out and stores it in the Kodi database.   The add-on ask Kodi for a bunch of information via a combination of Python and JSON calls.  For a song that has multiple artists, Kodi returns a list of musicbrainz IDs which the add-on then uses as needed.