You can edit the .SIF file associated with an installation image and thereby restrict the disk reformatting to be the same as what the source computer used to create the installation image. Open the file RISTNDRD.SIF and modify the UseWholeDisk parameter to equal NO. This option will cause the base partition for the OS to be the size of the one on the source computer, and the rest of the disk will be left unformatted. For more sophisticated partition management, you may want to look into a third part disk-imaging tool that is designed to handle such things.
This was first published in October 2003