Burning Image Files

.img files are problematic thought.
If you want to really make back ups, use astarte's CD copy application. It's an application worth buying if you making backups :)
Personally I mount the image and use Toast Deluxe to Disk Copy the mounted volume. You can do this with several images if you leave the CD open (write session, not write disk) and you will get multiple volumes to mount when you stick the CD in.

eMail me if you want more info.