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.
OS X 10.6 or later only. iTunes 10.3 or later only. Previous universal version available at the link below in the "Info" section.
Change video kind and video related tags of selected video tracks
App displays files in iTunes Media folder which are not in iTunes library
Continuously update your desktop picture to current track's artwork
Renumber order of selected tracks
Capitalize the first letter of each word in selected track names
Copy chosen tag info from one set of tracks to a different set of tracks