I wanted to report 2 internal cover art issues:
1. When I convert files from my APE collection (APE|PLS|APL, actually) to MP3, the cover art is sometimes removed from the destination files. It always happens on a "full album" basis, i.e. either all tracks from the album have cover art, or none of the tracks from the album have cover art. Unfortunately, I can't reproduce it because it seems to be random behaviour. I do have the impression that it's better in build 346 (I estimate about 10-20% of the albums have conver art missing) than it was in build 336 (I would estimate about 30-40%). I realise this will probably be hard to find and fix for you if I can't reliably reproduce it, but I decided to report it anyway. Maybe you do find something.
2. When I select more than one APE file from the same album (i.e. with the same internal image) and select file properties, the image is not shown (the text "Location: inside file(s)" is still shown, however). When I do the same thing with MP3 files, the image is shown. This behaviour has been present for all the v8 builds I've tried. I always assumed the missing image would be "normal" behaviour, until I noticed it was different with MP3s.
Listening to: 'Sober' from 'Undertow' by 'Tool' on Media Jukebox