Seriously ... Skip Some Photo Ops.
Be careful of the pictures you post on Facebook. You might want to initially shrug it off -- "Eh, just my friends are going to see it, right?" -- but consider this: EVERYONE is now granted access to Facebook -- this means parents, employers, coworkers, and so forth.
Risque pictures of you on Facebook can prove to be a problem if some of these people have access to your profile. If you still have a great need to post these pictures, then at the very least block your profile (you can find this in your privacy settings), so that you have to approve a person before he or she can see your profile.
That way, you won't put yourself to lose friends, respect or worse ... your job.