If you want to know who steal, use or duplication your design, we've launched a new product for that : SeoImage .
The beta version allow you to upload an image or paste an url and we provide every informations found on the web.
You can try it for free now, I'm the designer of the website, I'll be please to have some feedback from designernews's community (about the service & the design).
Update 18h40 : We've update the website thanks to your comment. Thank you :)