Here is a screenshot of two applications. On the left is Mp3tag, installed
under Wine, which is showing the actual embedded artwork for the track. On
the right is Banshee. I've imported a single album to the library, and
Banshee has needlessly downloaded album art instead of using the embedded
art.
http://farm4.static.flickr.com/3002/2840004685_715853148e.jpg?v=0
There is a clear difference, here. Amarok works just fine using the
embedded artwork. In fact, every application that I've used can see the
embedded artwork.... except Banshee.