I am trying to install Windows 8 using Bootcamp on an Apple machine. I need a bootable CD. Does the bootable CD have to be the size of the ISO image or can it be smaller (since it only contains the installer)?

If it does not in fact have to be the size of the ISO image, what's the minimum required size of the CD I insert into my drive to create a bootable CD? (i.e. the minimum size of a bootable USB is 8GB)