It does not make you gay. Look at all the heterosexual guys who have posters of their favorite athletes on their walls. It isn't any different.
I just bought a poster of a pretty girl with blonde hair and she's in a bikini. Would that make me gay? I mean she's a pretty girl but I like guys so I'm not gay?
If you're attracted to the opposite gender, your heterosexual, even if you are gay, it shouldn't matter
You could be Bi-curious if that's what you like that is your decision.