Man, this isn't right. I dunno what to tell ya if you won't fight it. I hope that if you truly do love the little girl who calls *you* daddy, that you do pick up. I know your options are between bad and worse...but still, I can't believe you're just giving up so easy. This is not right or fair. Even if she doesn't see pictures, do you really want in the future for the biological mother to lie and twist her mind? About you? About anything?
While it is your choice, you at least have a chance if you *try*--if you give up then you have NO chance.
Maybe I'm outta line saying this: if I had a daughter I loved like the way you sound like you love yours, I would do everything I could to fight to keep her. I would fight for someone I loved. If you truly do love her, you'll fight for her. ...Just my opinion. Take it or leave it.