Picture verification

[daytr1pper]

I've seen people call another out on pictures posted. The kind where someone claims it's them and someone finds out it's not -> that the perp is stealing someone else's pics.

What do you use to do that?

I've been swapping pics with someone and some of them look doctored. I'm wondering it's truly them.
If I use google, I get a message that searching for people is limited.

Thanks