Quoting Amαndα ♕:" Looking into it more, it is fake. But the link you posted (Stfu shirley) didn't prove it. lol I had to hunt it down. http://www.ar15.com/forums/t_1_5/1414864_Fake_Brady_Campaign_posters_.html"
I just copied the link the other person posted, out of laziness. But that link had the link you posted too, in the comments. When I first saw the rape poster, it took probably less than a minute for me to track down the information proving it fake.
Eta: It's never a bad idea, when you see something shockingly inappropriate like that, to do a little research on the source before jumping to outrage. The Brady Campaign would just never say that. I know this is a heated subject for just about everyone, but people are so quick to jump on whatever they see that helps them prove a point. Chill out and check your sources first, THEN get angry. Otherwise you waste so much energy. (Not speaking to anyone specific, just in general)