Ghost does this very well to both cd and DVD (both bootable) and accross a network with just a bootable floppy, I seem to remember it can repartition the drive too. Not opensource but quick easy and not expensive. I have used this many times in the past
I believe driveimage can also repartition the drive to how you want it too, and then restore the images.
I am assuming the target OS is windows based from your scenario as it is a small rural school, and possibly has NTFS partitions. Which is why I listed windows native options because of NTFS problems.