Dear Julie,
I have read your email and the responses concerning the illegal use of your photos, i.e. use without permission, which is a breach of copyright.
Google images has a search engine into which you can upload an image of yours and it will come up with all the websites where that image appears.
I did that recently with a couple of photos of parrots that I had placed on the Internet Bird Collection website. One search came up not with ten websites, but ten pages of websites, i.e. nearly 200 websites had taken and used my photo. A little more than half had left my signature intact, only one had acknowledged that I was the author, and the rest had cropped off the signature/watermark, or superimposed their own logo over the top. Few of these websites had contact details, and many were in foreign languages. And beware of some of these websites as I found out. A couple were bait pages to lead you into filthy pornographic sites.
As far as I can see, the only way to stop it is to not post your photos on the internet in the first place.
It seems we are trying to shut the stable door after the horse has bolted.
Best wishes
Margaret Leggoe