I\'ve been using mutagen for reading and writing MP3 tags, but I want to be able to embed album art directly into the file.
Possible solution
Are you trying to embed images into a lot of files? If so, I found a script (see the link) that goes through a set of directories, looks for images, and the embeds them into MP3 files. This was useful for me when I wanted to actually have something to look at in CoverFlow on my (now defunct) iPhone.