The total number of favorites mostly tell one thing about a (good) picture: how long ago it has been uploaded. If people order wallpapers by favorites (i.e. likes) they see the older pictures first, and if they happen to like them, that just aggregates more favorites, and the difference in favorites between newer and older pictures just gets bigger. (I still have the mental picture in front of me, where Barney Stinson, and some brain infograph were the top 2 pictures on wallbase for ever and ever.)
If you could introduce a new number that is the total number of favorites, divided by the number of days the picture has been on wallhaven, I think you'd get a much more impartial number. Even if there is a rush of favorites on recently uploaded pictures, which would place the new pictures on top of this list, this would normalize within days.
What do you think?