Tineye?

As Forest Gump says, "Im not a smart man....."

Ive heard about Tineye and people using it to discern that photos posted to BP or CL are actually stolen from another site.

Question is, if a photo appears on a web page or say social media site and its cropped to say, just a head shot.

Thas that pic in its full entirety letting it all hang out, so to speak is emailed to me, can Tineye catch the pic and match it up to the head shot?

Good question.

I cropped a picture and tested it.

TinEye found it. I will run some more tests and report back .
But, it looks like within reason, TinEye still finds it.

Yes, even if the image you are searching for is cropped, TinEye will usually be able to find it. A number of times I have found matches in TinEye that were a full sized version of the image I was searching with. A great example would be an image where the heads were cut off to hide the faces of the subjects but the matches in TinEye were images that did have the faces in them.

Keep in mind Tineye is not doing facial recognition analysis as that would be far too expensive for a free web service. What it is doing is using the digital signatures that you might find in the images were you to look. Even a cropped image retains some digital markers sufficient for identification using a product like Tineye.