Ok, I have tons of music and since I never actually organized anything until now…I went ahead and deleted all the media player created .jpg files, etc. so I had NO thumbnails.
But some of the albums already have the artwork embedded in file tags, which is the right way to do it anyway (the .jpg files only help Windows related apps as far as I know).
I made sure all hidden/system files were visible and deleted all *.jpg (as well as thumb.db) from my network server collection. All that is left are the pure folders and .mp3s.
I turn on the WD TV Live and navigate to the network server, go to the music folder, and all the old thumbnail images are still there. Ok, good - it must be reading in and displaying whatever image is inside the file tag for the first song it probably finds inside the folder, just like windows media player does when you use the library functionality.
Otherwise, where else would it get this info?
But I would go to existing folders with no image in the file tags and add an image to the tag of all the files and it won’t show up. Also, some folders already have images in the file tags and they don’t show up either.
NOTE: I would exit and re-enter the server so it goes through the ‘Connecting…’ and re-reads data back in,
How is it picking and choosing what to display as music folder images? And no, using folder.jpg doesn’t work for music, only video.
I have thumbnails turned on of course and set as the default for both browsing and selection. Obviously it works because it originally pulled them all in but it seems any changes I make have no effect.
When I go into browse via Windows Media Player the images show up as expected, and Tag & Rename also shows the images correctly as does MediaInfo.
What am I missing?
The docs say nothing of course and I’ll call tech support tomorrow but the only thing I’ll probably want to do after speaking to a ‘tech’ is call Homeland Security 
Ok, so I’m frustrated after spending 5 hours chasing my tail. That last comment was immature. Accurate…but immature 
