it is sometimes hard to know those media that are free to use. Although ,
Agree. Mistakes do happen. But we have repeat offenders ...
I have a peculiar case where one of the photos I took and that too of my feet is used by health care department for "anti mosquito" campaign. No one has asked me for permission. But I find it absolutely fine. So not all "plagiarism" is intentional and in some cases like the one I mentioned, it can be fair usage too.
So right but then , I think anyone who would not want his picture used , should have it watermarked and protected from search engine crawling. Good Post @bobinson