Here's a beautiful family photo. I'm not exactly sure who everyone is, but it's customary to take a couples photo, as well as a family photo. The only issue with that is when the family members don't dress up to the level of the prom-goers. It's not hard to look schlubby next to a girl in a gown and a dude in a tuxedo, so you have to bring your A-game. At least they have the classic prom pose down.
What's even more fun than taking normal prom photos is taking prom photos that make fun of all the cliche poses that you see year after year. I call this one the choo choo train. It's where everyone is connected, holding each other's hips. It is one of the most classic prom photos. It is perfect for large groups.