You absolutely have a legal right to your baby pictures. I suggest if your father is alive to immediately get them from him. Do not involve your stepmother and essentially arrange it so she is out of the home. If you have other family members who support your view, bring them with you to the home. If your father has passed, it is time to get some family member and go to the house and indicate you would like your pictures and leave it at that. If she feels threatened, she may either relinquish or throw you out. If you feel the latter will occur, consider talking to a lawyer about suing her for specific performance (return of your photos) or file a claim in probate court.