LaunchBox will only download and display region correct artwork for the game in question. Your region priority only comes into play if the game has multiple regions assigned, we will grab artwork in priority order (stopping at the first one with artwork). Otherwise, we only grab images that match the region or have the world region assigned to them if no region correct image is available.
If you ever want to actually SEE the images in the UI I'd just suggest leaving the games separated out, otherwise you are just wasting your time and drive space trying to get images for every region.