Filling out Christmas cards as a young, single adult woman?

This is the first Christmas I’m out of my parents’ house and pocketbooks. I’m sure no one in my family expects me to send cards, but I think it’d be a nice surprise. Normally I would ask my mom for advice on this sort of social nicety: However, I want to surprise her too. I know the basics of obviously addressing the cards themselves.

But what should I put in them? What kind of message? Should I include a picture? I know many people typically include pictures of their family, however, that’s not really an option. I feel like putting a picture of just myself would be egotistical. Would a group of me and my friends, my “family” here, be appropriate? Is there anything else I should consider before sealing and sending them off (after Thanksgiving, of course)