Is it ok to upload my yahoo pic of myself in my underpants on facebook?

[pri✍]

You should really consider your decision to put pic anywhere in the net, as once it's out there, no way to take it out, as everbody who can see it, can down load it or screen shot that. Just ask yourself, whether you don't have any problem when your parents see it, your (future) children, your teacher, etc? If the answer is yes or even doubt, don't do it.