Album art visible in some themes but not others (AWP, Sansa Fuze v2)

[Notary Sojac]

This is art from a separate file in the album subdirectory, -not- embedded

Art shows up fine (for example) in
Arbox Widgets
AW140

but not in
Boxamp
ART_fuze[1.1+]

I've tried all the variations on filename and filetype for the art I can think of. 

Sansa fuze v2 running 3.8.1, all the files are mp3 CBR if that means anything

thanks!!!