The only male had a picture of himself with someone else.

This corresponds to their personalities. Many of the girls I knew in high school were either self-conscious about their appearance and preferred to have other drawings/objects because those were cuter, or didn't like to take pictures by themselves. Of the two people who had pictures of themselves, not really selfies, one was fairly confident in her appearance and the other one didn't care.

In high school, I also had a picture of a drawing as my profile picture.