Browser folder art.
This is already kind of present on mobile, but I think it would be really nice if the folders in the browser displayed art from whatever files are in any subfolder. Right now, if an album is inside of a folder or something, its art is displayed, but folders above that level don't display the art. It's not the biggest matter, but can be convenient when navigating. I also think it would be nice to have the art displayed in the browser on the web as well.