The first demo video shows you how you can make navigational buttons in Photoshop using multiple layers in a single space. The second demo shows you how to create the same output files as in the first demo, but the second video uses “slices”.
BY THE WAY . . .. Even though in the video a talk about making “javascript rollovers,” these techniques are the same for making CSS hover buttons that use absolutely no javascript. So don’t let that throw you off!