So-called Computer Watermarks are not watermarks, per se. There is, of course, no logical way to embed an image in the structure of a computer generated image in the same way that a true watermark is embedded in the structure of paper. The term is used to describe either of two things:
1.) A webpage background which does not scroll along with the primary elements of the webpage. {Note: This works in Internet Explorer and certain other browsers, but not in some.}
This page and the main page for this html document have been set up for the background to function as a computer watermark. Notice how, when you scroll down or up, the background remains stationary and the words and graphics move.
The way in which this form of computer watermark is created in a webpage is to add the html code of {bgproperties="fixed"} to the page's source code.
2.) An image, consisting of either a word or an object, or both, which is created using a low density, or opacity, of color on a transparent background, which can then be superimposed over another computer generated image.