Also known as a favorite icon, a favicon is a small graphic associated with websites or Web pages. It is visible in the tab or address bar of an open Web page. Most favicons are miniaturized versions of a website's logo, serving as a marketing tool.
Favicons first appeared with Internet Explorer in 1999, and they are associated with what Internet Explorer calls favorites, or websites saved for later viewing. They are small images, ranging anywhere from 16x16 to 64x64 pixels. Designers create favicons using standard design file formats such as JPEG or PNG, but the images must be converted to the ".ico" format in order to be recognized and displayed by Web browsers.