TexasRockbox,
I had a little thought about this, and I believe I have come up with a solution that will suit your needs...
If the only .jpg files on your device are for the AA (which is likely, but not guaranteed) just do a search of your device (using your PC) for ".jpg", then bulk select them and change the file attribute to "Hidden".
This *should* stop them from being displayed when in the view mode "supported", I use this same trick myself to stop the iPods OF directories (Notes, iPod_Control etc.) from showing up in the file browser and it works fine for me.
I noticed this wee trick because I just drag & drop my albums straight out of my WMP library, and WMP uses the same naming convention (Folder.jpg) for its AA, but it is a hidden and system file.
I Hope this helps,
[St.]