Why do you need to read what's in the image to burn it? If you're looking for a command line CD burner, you can use cdrecord.
If you do indeed want to access the files in the image, then you mount it with the mount command (e.g. "mount -t iso9660 -o loop image.iso /mnt/tmp" will mount image.iso on /mnt/tmp). Read the man page for mount ("man mount") for more details.