
Method 2: Use Disk Utility Creating a Disk Image To restore a disk image, follow the above steps in reverse. If you want to create a disk image on an existing disk, then select a folder instead. If you want to create a cloned copy of the source volume, then select a destination disk, but be advised that existing files may be overwritten. To create a disk image, select the source volume and the destination volume. CCC has been around awhile, and has a simple yet powerful interface that can serve multiple functions, including creating a bootable backup from a disk (like your internal hard disk).

There are three methods that are described: Carbon Copy Cloner, Disk Utility, and CommandLine.

INSTALL CD IMAGE FOR MAC HOW TO
This gist details how to create or restore a disk image in Mac OSX.
