Why do some women make funny looking smiles for the camera (not trying to be silly, but actually trying to take a nice photo)?

I have a couple of examples of this:

1. In high school, I swear every girl liked to make an expression with worried looking eyes and eyebrows, yet with a smile. I don't know how else to explain it. Almost like that Hide the Pain Harold meme, lol. These were not their natural smiles, just for photos.

2. I've noticed more than one woman who widens her eyes to the point she looks crazed when she takes a photo (not trying to be rude, just trying to explain how it looks, lol). None of these women smile like this in organic conversation, only in photos.