if your dad will leave her, FOR SURE.. tell him, if not, and hes a forgiving pussie, blackmail her, big time, and make lots of copys of the pic, post it on the net, somewhere secretley if wanted..where no one could see it ( photobucket.com ) and then there you have it, legal blackmail.. no need to right up black mail, but insinuate what you want, give her the "idea" and make sure you tell her "you meen buissness...."