Anyone who creates an image should be concerned about protecting it. James Provost wrote an amazing post on the subject of protecting illustrations on the site TechnicalIllustrators.org. By making it easy for people to trace the provenance of the image, you can help ensure that it is used correctly.
The information James provides can certainly apply to photos as well as illustrations and offers simple steps to batching metadata using Adobe Bridge and setting up metadata templates in Adobe Photoshop and Illustrator.
Although this information is well covered, this post simplifies it to a step-by-step set of instructions with screenshots that will take very little time to implement for your own needs.
As James says:
There is little you can do to stop someone who is determined to steal your images. Watermarks are easily removed and website scripts are defeated with a simple screen grab. These attempts only mar your work and make your site difficult to navigate.
In this tutorial I’m not talking about protection from image thiefs, I’m talking about protection from lost opportunities. Times when your images are inevitably downloaded, blogged, cropped, reblogged, faved and saved, and end up orphaned on someone’s hard drive, ffffound, imgfave, tumblr, or email—especially when that person likes your work and would really love to hire you, if they could just figure out where the image came from.