Atlus has a web mini-game for Persona 4 Arena where players can try their luck at winning wallpapers. You can play the game and visit the Velvet Room here.
Igor will give players three chances to shuffle the cards. Get three cards representing the same character and you’ll earn 5 points. Match two out of three characters for two points. If all three cards are different you don’t get any points. Earn ten points and you’ll unlock a wallpaper. That’s probably not going to happen on your first play through, but you can try again tomorrow when Atlus gives you another three tries. (If anyone unlocks wallpapers maybe we can share them here? I’m halfway to Labrys and Akihiko’s wallpapers!)