If it's somebody you know, and they saw you taking the picture (at a gathering of friends, etc.) - particularly if they posed for it - these days it's a given that it might get posted to your own social networking sites. In that case I wouldn't say it's rude. Putting the pictures on other sites to make fun of them is a different matter. Also if there was anything potentially embarrassing about the picture. If they wouldn't want their parents or their boss seeing it, don't post it anywhere at all. And if you don't know them - and they are anywhere other than in the background - then it's just creepy. I crop my pictures before I post them to try to remove extra people if I can.
It is becoming so common place You can be walking and then a someone will see something funny looking Whip out the phone and trying to post it to facebook they do it with out nary a thought of what the subject of the shot would think or feel about it. This is just out insensative we are Rocket River
