picture of them on the internet? I need this for reference in a social education research topic.
If somebody posted a picture of you on the internet, and refused to delete it, would you be able to sue them? And what would happen is the image became very popular?
Well, it would depend on the person photographed and how the photograph is used. In the case of a celebrity, it might be a breach of trademark protection http://en.wikipedia.org/wiki/Trademark. You need to provide wayyyyy more facts for a more considered reply. Generally, though, if the photo was taken in a public place and it's not used in a way that might be considered defamatory or otherwise harmful to the person depicted, no one really cares. Authorities just have no time to pursue the social networks online unless there is some sort of harm or danger of same.