For macOS 10.10 and 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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Batch-change the Album Rating for the albums of selected tracks
downloaded 23m 45s ago
Convert selected tracks and export the converted files to a new folder
downloaded 39m 42s ago
Re-associate batch of dead tracks with files from selected folder
downloaded 1h 38m 40s ago
Add or subtract a user-entered number from each selected track's Plays
downloaded 2h 3m 2s ago
Export selected playlists as individual XML or M3U files
downloaded 2h 6m 23s ago
View/Edit tags of selected track(s) in single window