Definitions for "Web Bugs"
Web bugs are HTML elements, often in the form of image tags, that retrieve information from a remote web site. While the image may not be visible to the user, the act of making the request can provide information about the user. Web bugs are often embedded in web pages or HTML-enabled email messages.
A small image in an HTML page with all dimensions set to 1 pixel. Because of its insignificant size, it is not visible; but it is used to pass certain information anonymously to third-party sites. Mainly used by advertisers. Can also be referred to as a Web Beacon or an Invisible GIF.
Images fetched from a remote web server that are used by commercial organisations to monitor people's use of websites.