Related Clues:

• Happy face feature
• Sit for a picture
• Flex one's muscles, maybe
• Ask
• Present a problem
• Thing to do before the picture starts?
• Do some modeling
• Example of model behavior?
• Put forth, as a riddle
• It's uttered before the flash
• Show approval, in a way
• You strike it by remaining still
• Let it be your umbrella
• Grin
• React to "cheese"