I had found one of my photos on another website by sheer accident one night and they had obviously downloaded it from something like GOOGLE or Bing and no info was pasted up with it. But pointing out that it was my photo, I then got an Email from the site owner asking for permission to keep it up after I joined the site that is and I said yes keep it there you are not selling shoes souls or what ever but a sort of historical site and the photo was historical. I lost nothing at all I still have the original photo, about the only thing I have lost is a payment for using it but I am not greedy that way. Just glad that someone thought my photo good enough to use actually.
Not all would agree with me though, but a lot of photographers have huge ego's at times over a simple photo. As long as they do not download and use all my photos in one go, then using just one is simply a sample under the Aust Copyright laws.
I should add that how often have you read a book which has a few lines from someone else book on a similar subject mainly historical type books where Joe Blow stated in his book little know facts about the trains "that trains run on specially made tracks on a bed of crushed rock". Which is word for word as Joe Blow wrote in his, this is allowable, but copying a whole chapter or a page or something is not though. This is simply sampling the other work.