The bot checks the posted photo against Google reverse image search. So you will know if the photo is original content or taken from somewhere else on the web.
Right now the matching is done by Google, but I'm already working on additional checks to be more sure about the matches. For example, it's not 100% perfect now with sunset photos right now, because they all look so similar :-)
I never realized that Google made this functionality open to the public. I've been seeing them use it for a number of purposes in google images lately. It's so good that it's a little spooky at times. I think it's time for me to deep dive on Google Cloud Vision.
BTW, what are you tying into that triggers the bot on each post?
For getting the latests posts I use piston-lib, here's an example: http://lib.piston.rocks/en/develop/quickstart.html#waiting-for-new-comments
Wow, this is great! Thanks for pointing me to this documentation.
Please do not just react to your fears of your work being stolen and think about what he is really doing.
Please read my other comments on the page you made your post. He is not using his bot to stop plagiarism. If he were, he would not be embarrassing posters who do give source or get their images from sites like pixabay, who allow their images to be used.
All he cares about is that he has found a way to grow himself here super quick, and he does not care how many posters he damages with his suggestive comment (plus the implied threat by his posting the link to steemcleaners.). Most posters lose it, get afraid, because most are new. This is bad and I just wish I knew who to contact to stop this abuse of posters by him. I guess I should maybe ask @patrice, she'll know.
I'm trying to go to the posters he sent his bot, to reassure them (if they are legally using the images) but I cannot keep up, the bot is distressing hundreds of posters without reason.