Song pages deserve better quality assets.
In my opinion, JDU assets (in PNG format) should go on the respective song's page.
If there are differences between two squares, add both to the song's page.
Game pages can have the square that belongs to the respective game, for example, Just Dance Now's pages will have the squares that are from Just Dance Now. Just Dance Vitality School pages will have the squares that are from Just Dance Vitality School, and so on..
A decision of updating the assets for better quality ones on song pages was implemented back in December 2016, you may find the thread here. I agreed with this thread, and I will finish the job.
In the same thread I mentioned before, there's CwM's opinion on the matter, "The squares are from JDN so they should stay on the JDN page.", to which I agree 100%, and that's the way it'll be.