being bi, gay or straight is not about image. there are plenty of "femme" lesbians, and there are plenty of straight "tomboys."
As for your sexual orientation, you are what you think you are. if women turned you on, and you think that's the thing for you, fine. if you're all about boys, that's fine, too. If you like aspects of both, that's also A-ok. If you are convinced you are bisexual and want to call yourself bisexual, by all means do so. After all you know yourself beter than any of us would
on the flipside, have you considered that it's the way the pornography is presented that may affect how you see it? Maybe you prefer something that's "nicer" than "nasty." perhaps something more "tasteful." if you find something you like, you might find yourself just as attracted to pornography featuring male models.
Have you read the articles in Gaydar?
Color is for crayons, not for people.