The Trent University demo and my simplified version work in Internet Explorer and Netscape browsers prior to version 6. But Mozilla 0.8, Opera 5 and Netscape 6 browsers don't recognize the code as written, and it would take a bit more coding to extend the copy protection to these browsers. Doing so would no doubt discourage the casual borrower, but not the serious crook. But try it a second time. Embed a Watermark.
Many image editing applications provide a watermarking option.
Briefly stated, Digimarc's ImageBridge system embeds an invisible watermark in your image. If you subsequently find your image on another site, you can read the watermark to verify it's yours. Then call your lawyer to proceed to step 2. As with many other schemes, ImageBridge is no match for the serious crook, but it may work well enough to help you police amateur burglars. Visit the Digimarc website for more details, or read the Digimarc ImageBridge review here.