It's best to not add people
It's best to not add people that you haven't met as friends. The reason is, you might not know them. They might Hack you or sell your info to someone. However, I'd prefer to add people I've only met.
if you give someone strange
if you give someone strange your photo around the place you live, they might still you! so be careful and NEVER publish your personal info with ANYONE, even don't give them to the online friends you trust