Watermark
1. An image or text, such as a logo or the date, superimposed on an image that is used to help prevent an image from being copied or to allow others know where the image was originally from or who owns the rights.
In the picture to the right, is an example of such a watermark.
2. An image that has a fixed location and does not move along with other content. Watermarks are often used on web pages so that the site's logo or banner is always visible in the background.
Also see: Copyright