Anything with "No Album" is geting the same artwork

Anything that is designated as having "No Album" is getting the same artwork, and figuring it out is driving me bonkers.

I've checked individual mp3 tags and no image is set there.

I've deleted artwork.db and rescanned

The "No Album" image file comes up as "http://LMS:9000/music/1a6e25b3/cover_150x150_o"

Under Server > My Music > Compilations
[ x ] List compilation albums under each artist
[ ] Group compilation albums together

There is nothing in the tags listing all of these songs as No Album, so I'm guessing it's an LMS setting somewhere, but I definitely can't find it. Help!