The Photoshop "Save for Web" Feature
http://www.elated.com/tutorials/graphics/photoshop/save_for_web/

Elated
2000

Abstract:

As of version 5 and greater, Photoshop includes a very handy Save for Web command. This feature allows you to produce a copy of your image that is optimised for web use. This means that the image file will be as small as possible, and that the image will use only web-safe colours (if desired). Save for Web can produce GIF, JPEG, or PNG format images.