I was trying to mount a partition within an image like this:
# mount -o loop,ro,offset=XXX
whereby I had to calculate XXX with values obtained from "fdisk -l <image-file>"
Turns out there's a MUCH easier method:
# losetup -f -P <image-file>
which will give you /dev/loop0p1 and /dev/loop0p2 (in my case there were 2 partitions in it), which you can then mount as follows:
# mount /dev/loop0p1 /media/rasp1/
# mount /dev/loop0p2 /media/rasp2/
😎