Say you have a disk image created using ‘dd’. You want to mount a partition contained on it but you realize it’s not as simple as just mounting the image and exploring the path.
The kpartx utility can help with that:
sudo kpartx -av disk.img
This should have created some partition mappings to /dev/mapper. Now, just mount the correct mapping the same way you would mount anything else. For instance:
sudo mount -t ntfs -o ro,noexec /dev/mapper/loop0p1 mounted