Disk imaging when used in automating Windows XP deployment is the process of creating a master system, duplicating the files, and distributing the resulting system image to additional machines. The master image can be distributed using a disk-to-disk copy or by using disk-imaging software to create a disk image file. Most currently available disk-imaging software allows you to create a compressed image file, which can then be distributed from a shared network location or by copying the image file to CD-Rs.
Just to be clear about this, the Windows deployment tools provided by Microsoft only take you as far as configuring the master system disk. You'll need to get a third-party program to make copies ...