OS X 10.8 or later. This script will look for an image file in the parent folder of each selected track's file--presumably its Album folder in which you have previously placed an image file of some sort--and apply the data from that image file as artwork for the track.
Perhaps Also of Interest...
downloaded 32s ago
Convert selected tracks and export the converted files to a new folder
downloaded 45s ago
Set the Album Rating for the album of a selected track to full- and half-stars or computed clear-stars
downloaded 17m 0s ago
Change file type to make selected AACs bookmarkable
downloaded 25m 59s ago
Send current song info to clipboard
downloaded 29m 8s ago
View/Edit tags of selected track(s) in single window
downloaded 30m 33s ago
Display, create text file listing info of dead tracks