This function is used to extract artwork from an Apple application and replace the existing artwork.
The function only extracts artwork for currently selected files which are linked.
Note: In order to make the process faster, the function will only extract the artwork once per album. The artwork will then be replicated to all tracks in the current selection which are in the same album, whether they are linked or not. If the Apple application does not have artwork for an album, the current artwork in the selected files will not be deleted.