Check out this nice piece of fan-made art for a World's Finest movie starring Ben Affleck and Henry Cavill. The actual Man of Steel sequel is supposed to be more of a Batman Vs. Superman film, inspired by Frank Miller's The Dark Knight Returns. The poster was created by BlackJack10 (via CBM).
Here's some information on the poster from the guy who put it together:
Affleck in the Batsuit was made by rcazzy from SuperHeroHype. Cavill is an un-used Man Of Steel promo image. Background is just a random storm that was brightened up with after effects all logos are just random google searches that have been re-rendered or colored.