I am thinking beach theme. Have her wear her favorite bathing suit or summer time outfit. Bring sun glasses, beach chair, buckets w/ shovels, beach towel, beach bag, a beach ball, small blow up pool etc. That would be fun. Or you could do a birthday theme. Bring balloons, streamers, party hats, confetti, a large number 5 (cut from poster board), have her wear her favorite "Big Girl" outfit or let her dress herself that would a hoot. Maybe add a birthday crown and a few cupcakes. Decide what you want the picture to be about and bring props for that idea. What does she love to do? If it's ride her bike then bring the bike, helmet, elbow pads, box of bandaids, etc. If her favorite thing to do is play outside bring boxes of chalk, bubbles, hula hoop, jump rope, wagon, ball, roller skates etc. Hope that helps or sparks an idea for you.