As a Stepmother am I allowed to post up pictures of my stepdaughter without her moms consent?

I am a stepmother of a 2 year old and I am curious to know if it can be a legal problem (especially in Texas) if I post pictures up of my stepdaughter on a social networking site without her mothers approval. We have her for the summer and of course I love to take pictures of her and her new little sister together and be able to show them off but would it be possible for the mother to use that against me?