Years after the rest of the planet made "stoic" passport photos fashionable, the US has finally begun following suit. At one time, a big 'ol American smile was acceptable in US Passport Photos, but not any more. The newest regulations require a closed mouth. They still appear to allow a slightly pleasant, closed-mouth smile, but no more grinning with teeth. Still not quite as strict as the rest of the planet, but getting there.
It seems the customs folks are using facial recognition software to scan the passport photos, looking for bad guys, and of course, bad guys NEVER smile in their photos, so it stands to reason that they don't want anyone else to either.
In any case, learn to smile more with your eyes, and less with your mouth. You local US bureaucrat will love you for it.
For the very best US Passport photos on the market, call a real photographer. Call Newsome's Studio of Photography at 813-968-2810. Located in North Tampa (Carrollwood), at 10012 N. Dale Mabry Hwy, Suite 219, Tampa (behind Starbucks in Cypress Point Office Park, at the corner of Linebaugh and Dale Mabry Hwy).
Think happy thoughts!