Register a watermark and then apply it to each image that you want marked.

I registered with Digimarc, using their free, one year subscription service.

When I finish creating an image, I click on Image>watermarking>embed watermark. Fill in the appropriate numbers (assigned by Digimarc) in the proper places. Click OK.

Another way to mark an image is create the image, then click on Image>Image Information>, then click on the Creator Information tab. A form window opens. Fill in the form and click OK. The information is stored with the file.

The background image that is used for the background of this web page is watermarked AJ Designs.