I am sure you have scene pics of girls that show them clothed and then pics that show their bodies but how do you know its really them? Some times you find distinguishing characteristics that nails it down. So you know that even though they were trying to hind some or all of their identity there is no doubt its them.
Here is the first one I found. She will show her tits but tries to cover her face when she does the more graphic stuff. However, she has a birthmark on her ass that can't be denied!
If you find more of these please add! It can be anything from clothes, jewelry, tattoos or even a birthmark!