Adobe Illustrator CS4 Slices
Using Adobe Illustrator CS4 for web design during template / skin / layout creation would be very difficult and tedious, were it not for “Slices”.
You can draw slices in Adobe CS4 after a mockup has been approved, and use the Save for Web & Devices window to fine tune the name and type of each slice, as well as select the format for each image slice (png, jpg, etc.). For more in depth instruction and details see the Adobe help article.
The example graphic here shows a blank website template that has been sliced into the appropriate portions needed in the XHTML/CSS layout code. Typically we create our mockups for a design like this in Illustrator, and being able to then clean-up, finalize, slice, and save, right in Illustrator, is certainly a handy process to know about.