Your problem is not a surprise for me, everything seems free on Internet :-(
Often I use search engines to look for infringements about my photos...
And currently people "take" some of my pictures for their website.
I send a e-mail to them and we try to find a solution.
Sometime I sell and often I offer but I like to give permission before !
The rules of copyright are written on my website, perhaps they have difficulty to read ;-)