One of the best imaging applications I’ve ever used and it’s Open Source Software and FREE!
Clonezilla and my favourite for doing a quick image backup of your computer is Clonezilla Live.
From the Clonezilla website here is a quick description:
Clonezilla live is suitable for single machine backup and restore. While Clonezilla SE is for massive deployment, it can clone many (40 plus!) computers simultaneously. Clonezilla saves and restores only used blocks in the harddisk. This increases the clone efficiency. At the NCHC’s Classroom C, Clonezilla SE was used to clone 41 computers simultaneously. It took only about 10 minutes to clone a 5.6 GBytes system image to all 41 computers via multicasting!
More Info and Downloads at http://clonezilla.org/