There's:
"No, I am smiling. What do you mean I look like I don't care about this? This the best approximation of my real grin I can do!"
And then there's also:
"Yes I know it's a fake smile and I end up seeming angry, but I'm baring my teeth, can't that be enough?!"
Oh, and don't forget:
"Oh, I'm actually sincerely laughing in this picture . . . I look like I'm in pain."
And finding a picture for online, come on.
"Oh! Here's one where I'm smiling for real, and have a face that is relatively free of acne! It might be from two years ago, but, where else will I find one where it doesn't look like I'm chewing on something?