Most people are familiar with the standard passport photo: a serious-looking portrait with a blank background. But what many people don't know is that you can actually smile in your passport photo. There's no rule that says you have to have a stony expression in your passport photo, as long as you follow a few simple guidelines. First, make sure that your smile is natural and relaxed. Avoid showing too many teeth or looking too stern. Second, make sure that your eyes are visible and that your facial features are clearly visible. And finally, remember that you'll need to remove any glasses or hats for your passport photo. So go ahead and smile - it'll make your passport photo a lot more memorable (and friendly-looking).