Books 2 Byte
Photoshop CS4 Bible
Stacy Cates, Simon Abrams, and Dan Moughamian
ART OF SLICING
Ask Stacy Cates, Simon Abrams, and Dan Moughamian, and they'd talk about four types of slices, viz. user slice, layer based slice, no image slice, and auto slice. "To create a slice, select the Slice tool and draw a rectangle around the portion of the image that you want to treat as a distinct region," they write in Photoshop CS4 Bible.