when someone sends in an anonymous picture. Especially when they immediately 'find' it and act all affronted by it.
Reason being, none of the pictures are labeled so there are no tags that would come up on Google. How could they possibly find it so quickly?
Plus, if you're not thrilled about it, why would you then point it out to other people to see it?
Always makes me think they sent it in themselves and want to pretend that someone else did it.