Artwork and Asset

I use Asset and Minim.  With Minim I (generally) get the artwork showing in the top level files and I can browse by album cover.  With Asset, I only get the standard file icon at browser level but when I play a piece the artwork then shows

The covers are are jpegs or pngs and are stored with the name "cover" or " folder" as I believe this is all Minim reads

Any help would be appreciated