reinstall from an image

I read that you can make a image of your OS and reinstall it if there are problems - sort of like Ghost.

Making an image seems fairly easy, but how would I reinstall it?

I have it on a USB drive, do I boot to USB? I imagine I would have to mount it before I could do anything with it.

thanks
J

This is how I imagine it would be.

You boot into the OS X install DVD.
Connect the USB drive.
Open Disk Utility
Go to the "Restore" tab.
drag your disk image from the USB disk.
Drag in your mac disk into the destination.
"Restore".

I'm not sure if this works, but it should.

I think you got it right there goobimama