It's hilarious to watch a group of adults try to get anyone under the age of 6 to smile for a picture. Jumping about, making funny faces, snorting, whistling, clapping, whathaveyou. Might be kinda fun to take some sneaky candid shots of the people behind the camera next time.
With my kids, I ALWAYS say, "smile big!" Sometimes it works, sometimes not.
Ok honey, smile big so Mama can take a picture!
Uh, not quite hon. You're scaring the people. Try again.
OK little Lady, let's take a picture of your cute new dress, shall we? Smile big!
Hmmm. I get the whole "girls are more dramatic" thing, but let's try that again...this time in the bumbo. Smile big!