I think the one on the bike is the best of the bunch. She doesn't do herself a favour with those photos (or the photographer isn't doing her a favour). She has a hard look to her anyway because of her gauntness and the jagged haircut, thin face,hard looking boobs. What she needs I think is something softer in a picture to counterbalance that.
I don't think staring someone down is ever sexy and that's what those photos look like to me. She needs a softness in her eye or look somewhere which makes her inviting/approachable and it just doesn't come across to me in those photos at all.