Here is how to track down your art wherever it's being used on the internet, and what to do about it:
- Go to whatever page you have posted your art (facebook, your website, wherever).
- Right-click on the image and click "copy URL".
- Go to images.google.com
- Inside the search box where you type your text is a camera icon; click it.
- A new search box opens up, right-click in it and click paste.
- Now click the blue "search by image" button.
I usually word my firm request this way:
The image of the (brief description of the artwork) on your (website/blog/page/pinterest board) is my original, copyrighted artwork. You are using it without my permission. You are required to either credit me and link to my website (list your website) or remove the image. -Cheryl CaseyAnd I don't sign off with "thank you" as I'm not feeling very thankful to that person at the moment. It is a demand and you have the right to demand it.
Also, if the content of the page where they are using your image is inappropriate or offensive to you, skip the part about crediting you and linking to your website and simply require that they remove the image.
It can take a while, depending on just how "viral" your artwork went. But give it a shot and take it one page at a time.
Good luck, keep showing off your artwork, and keep tracking down copyright infringement. Somebody has to educate these yayhoos.
Another good article on fair use... http://artlawjournal.com/internet-meme-getty-letter/