Have backups made by CloneCD?
No clue how to convert them to ISO images in Ubuntu ?
Actually its very easy:
Make sure to have the multiverse and universe repositories set up.
sudo apt-get install ccd2iso
ccd2iso foo.img foo.iso
Thats it 🙂
Your foo.iso is now ready to be burned.
I’m pretty sure most major distros have this package available.