Why are women so insecure when taking photos?

I was at the beach today and there were a bunch of people in a group I think celebrating a birthday party and one of the guys said let’s all take a picture and all of the women told them to wait and they all ran to their towels and put on a shirt over their bathing suit and ran back to take the picture. While all the guys were just looking at them dumbfounded. Like how sad is that?