This is not a plagiarism control bot. He is attacking ALL posters (many hundreds within a few days) who use a web image, such as, from pixabay who allow it, knowing it will cause them embarrassment, so that other viewers think the poster stole the picture. This is all for his own profit - just look at how quickly his rep has gone up -did you go from 25 to 44 within a couple of days? He is using technology for his own benefit, without caring how many innocent people he maligns by implication.
Please do not just react to your fears of your work being stolen and think about what he is really doing.
I actually hope that his intentions are good, because royalty free images are given for free to use on authors behalf. So if you do a reverse search on royalty free image, it would produce hundreds if not thousands of results. (people that used the same royalty free photo) You have a good point here. Update: I have even tested it now and for a single pexels royalty free image, it found me a astonishing 100,000+ similar images. Wow!
I'm sorry, it may be cynical of me, but the way he went about this, from the first day he joined steemit, it is obvious he came aboard with a plan for making his Rep and profit quickly. He may improve his bots as he goes, but what about those he damaged deliberately, without caring about them?
He should reverse ALL his comments (over 500 last time I looked) and only once he has perfected it, should he ask those who deal with this kind of problem and once they approve and appoint him, can he go ahead. Otherwise, I am letting all posters know that they should Flag him.