When I say a disk image, I'm referring to duplicating the data from a source CD to a destination CD exactly. Sometimes when you copy a CD, it doesn't copy exactly like the original. For example... I have a game CD that I would like to copy for my Daughter so I can put the original away. I really don't want her using the original as I'm afraid it might get seriously damaged. When I copy it and try to use it, the application on the computer can see it's not the original disk. If you lift the disk image and write it to a blank disk, you've made a exact copy that the computer sees as an original.
Thanks,
Tony