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.
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downloaded 1m 52s ago
Remove iTunes tracks disassociated from files
downloaded 17m 8s ago
Copy chosen tag info from one set of tracks to a different set of tracks
downloaded 31m 20s ago
Exports and then re-imports selected tracks' artwork
downloaded 34m 13s ago
Locates pairs of track entries pointing to the same file
downloaded 37m 5s ago
Gather all tracks of selected tracks' albums to single playlist
downloaded 1h 0m 39s ago
Export album artwork as folder.jpg to Album folder