UPDATED: Save Album Art to Album Folder v4.2
Save Album Art to Album Folder v4.2 exports the display artwork (the first artwork of a track) of the selected tracks, or the tracks in a selected playlist, to either the track's file's folder (presumably its "Album" folder) or a user-chosen locationthat is, all artwork will be exported to a single chosen folder. Various tweaks to the exported image can be made beforehand:
This latest version now floats above iTunes while running and has some minor code finesses.