Family Portraits

Some portraits have more than one sitter, as in Portrait of a Woman and Child by the artist Anthony van Dyck.  Many portraits with more than one sitter are family portraits, like this one of a mother and her child. 

Who do you think is doing a better job staying still for the artist?  How can you tell from looking at the portrait?

Do you have any family pictures in your home?  If so, how are they similar to this portrait, and how are they different?

If you were going to commission a family portrait, who would be in it?