I've been designing web sites for almost a decade using Illustrator &
Photoshop. Why should I use Fireworks? The promo copy reads: "the ideal tool
for creating and optimizing images for the web and rapidly prototyping
websites."

Doesn't Photoshop already optimize my images for the web? What am I missing?
What is "prototyping"?

This is a sincere question. I'm just trying to understand what this product is
and what it does. Thanks for any replies.

Max