Am I missing something, or do you really need to go through this process for every song...
Update to media library
Make a note of MP3, OGG, AND cover art link
Manually input each of these for every song, and be sure to not make a mistake or you'll need to start over.
It looks like a great plugin with lots of potential, but it was a pain to just add one song. I'm not sure why there isn't a simple option to choose the songs and images from the media library?