@yannick, How on earth is this “a dumb question”? This is actually a very interesting question and, almost more importantly, one that doesn’t appear to have been asked before (which is becoming increasingly rare).
To answer, I’ve never posted photos of myself but I know someone who gave the whole “adult friend finder” thing a try. Supposedly, she posted up a couple photos and a couple weeks later was contacted by an old elementary schoolmate who recognized her. I guess this guy was still in contact with a couple of her friends and passed the photos around via email. Suffice to say: she was not amused. Luckily her friends are really cool people and didn’t perpetuate the ordeal.
So basically, if you’re not ready to have someone you know find them, its probably not a good plan. If you’re comfortable with it, though, that’s entirely your business as far as I care.