Support for local artwork

[usayd-l]

When using local files can you add the feature that it uses local artwork as well instead of some random artwork from the same artist.

[NextFire]

#50 We chose in the end to rely on the open MusicBrainz database which already hosts many album artworks.
If yours doesn't appear, please retag your files with free open-source MusicBrainz Picard and/or upload your artwork to the database.