I stumbled upon a website that scans the web for photographs taken with your camera, should you happen to know the serial number of it and the pictures have their EXIF data intact. The website is called Stolen Camera Finder for the obviously named purpose but the site may also help in finding stolen photographs under copyright.
That’s the theory anyway. I have not been able to test this as I haven’t had a camera stolen nor do I have any of my pictures on the Internet.
Also, I have not been able to test this using a picture I have found on the web because most people optimise images for the web and this means deleting the extra data that holds this information, the EXIF data. When you take a picture, the camera records extra meta-data describing the photo into the file such as location, zoom, lens type, focal length and the make, model and serial number of the camera.
But in the event you have had a camera stolen and you recorded the serial number and then somebody has taken pictures with it with the EXIF data intact; just give it ago. It may just lead you to somebody you want to hit really hard.