I'm not sure (although I would have like to have tried), but I think yelling "GET YOUR CLOTHES ON RIGHT NOW AND SMILE SWEETLY AND ACT LIKE YOU LOVE YOUR PARENTS! RIGHT NOW! DO IT!... pretty please?!?!" I'll buy you a donut afterwards!" would set a negative tone for family pictures. You would see the tension behind the forced smiles and the boys holding back tears.
Anyway, as frustrating as that morning was, we got some beautiful pictures of Greyson and a story to tell the boys when they're older about why they aren't in these "family" pictures. And instead of donuts, we stopped and got breakfast tacos for Ryan and I and went home and fed oatmeal to the boys. :) I promise we are loving parents who love ALL of their children.