According to How can I mount a filesystem, mapping userids? :
I need to mount image file and share the content in the samba tree.
The thus, I need to remap original "user" to local user "nobody".
apt install bindfs
root# mount -o ro /dev/loop1 /mnt/1
root# bindfs -u nobody -g nogroup --map=user/nobody /mnt/1 /data/samba/tree/mountpoint
