When I was young, my father would take our photos during Christmas. He said that those pictures will be part of our family's history. There was no digital camera yet and he borrowed a camera from their office (he worked in a newspaper company). I guess the annual pictorial for the family should be practiced.
Family picture is very important for posterity. Since our children's formative years, I took their pictures especially when they're having their birthdays. When they've school activities and received academic honors, I never miss that momentous events. I right away document them by taking pictures. Now they've grown up and have their own family. They're doing that too.
Ah yes, but with the popularity of phones that have cameras then it's really easy to have "family portraits".
We used to do this when I was I still very small, but the tradition came to a stop as I got older. Nowadays, we just take photos randomly, and send them to each other, or upload them online and tag everyone.