The web tools in Adobe Photoshop CS3 can help you design and optimize individual web graphics or complete page layouts. Use the Slice tool to divide a graphic or page into seamlessly interlocking pieces and apply different compression and interactivity settings to each segment. The Save For Web & Devices dialog box lets you preview different optimization settings and adjust color palette, transparency, and quality settings before saving in several web-compatible formats.

Check out more detailed information courtesy of the Adobe Resource Center