Missing Album Artwork on Import

I’ve imported a sizeable library from iTunes into the Engine Prime software and around half of the tracks (10K ish) have had their album artwork stripped away. This is painful as I rely on the visual aspect as an additional element of familiarity with my collection. It took a lot of messing around within iTunes to track down the images iTunes couldn’t find, so I’d rather not lose them.

Is there a simple and quick way of retrieving said artwork? If it’s down to an arbitrary 1MB file size limit then Denon should consider increasing it.