1 You can report him to the police stealing something is a theft, a crime. Stealing a memory card is theft as much as would be stealing a $20 bill. The police may be able to get the card back, or at least out of his hands.2 If he does post any underage pictures of you, you could of course report him to the authorities for child pornography.3 If posts adult nude photos of you, but did so having stolen them, you may be able to sue him invasion of privacy.Yes, if you see anything posted, definitely take and save a screen shot as evidence.