MMA Pro album thumbnails

[hdubnow]

I have a question that has been bothering me on MMA. I have a question on the little versions of album art (thumbnails?) that show up when you select Album Artists, Composers, etc. from the MMA main screen. How do the thumbnails get generated, and why do some get generated but some not? I've tried correlating why some get generated and some not (size of album art, tag details, etc.) but it just seems to be random. I'm sure I must be doing something wrong, but I've no clue what. I checked for others having similar problems and I don't see anything similar. By the way, I always see the correct album art when I view by album -- the problem only shows up for the thumbnails.

I sync from MMW Gold Lifetime (currently 4.1.18.1852) to MMA Pro 1.3.1.0745 over WiFi but this has been happening since MMA Beta days in various forms.

Any insight what I might be doing wrong would be appreciated. I would love to have the album art in MMA looking right once and for all!

Thanks in advance!

-Harold