All rhythmbox covers are held in a database format called trivial database.

This database is found in the folder ~/.cache/rhythmbox/album-art.

In theory you can write some code or use tools such as [tdbdump](http://manpages.ubuntu.com/manpages/precise/man8/tdbdump.8.html) to interrogate the database, but in practise it is easier just to delete the folder and its contents.

Don't worry - it recreates itself when rhythmbox starts and you next add album-art.

If you are using Rhythmbox v2.97 and later you can instead drag-and-drop pictures from Nautilus onto the album-art plugin and it will update your album-art - make sure you are playing your music track first when doing this.

If you are using Rhythmbox v2.96 you cannot use this drag-and-drop technique. However, if you use my rhythmbox plugin coverart-browser, you can similarly drag-and-drop pictures onto your albums.