This is a little tutorial I did for our friend Aging One. Problem is the other thread was over-run with senseless chatter and got binned. So this is how to protect yourself from just any ol' person getting into your photos. I'll do another one soon about how to guard your personal data and personals, like where you work and what you do and where you attended school.
You just click up there and a menu drops down. There you'll see some options, like WHO CAN SEE MY STUFF. Click it.
Now you get this. See where it says PUBLIC, FRIENDS etc? Just pick an option. PUBLIC I believe is default. See, if you don't do this anyone who knows your name can search you and see your stuff. Now if you're paranoid or pissed on a daily basis you might twerk and think someone has hacked your account when in fact it was your negligence to fault. Hope this helps!