I tried
$ mount -o loop ./live-cd.iso /mnt
on a Live-OS image, which failed:
mount: /mnt: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
The image file is not corrupt.
In my case it helped to use kpartx (install with sudo apt-get install kpartx or sudo pacman -S multipath-tools or ...):
$ sudo kpartx -av live-cd.iso
which created a loopback device at /dev/mapper/loop0p1 (might also be at /dev/loop0p1) and then I mounted that instead:
$ sudo mount -o loop /dev/mapper/loop0p1 /mnt, which worked.