I have over 1000 pages in the Pokémon Mystery Dungeon: Gates to Infinity page, but can't select a header image there. It is perhaps relevant that that page is among those in which I lost a bunch of points - I used to have over 1500 points in it until that bug hit. Thought I would report this here.
On topic, I propose this image for the Poker Night 2 page. If I fiddled with it a bit more maybe I could get it to center slightly better, but I think as it is the image works pretty well across different resolutions.