Yes.
and on shutdown and on bootup and is configured to image only root (/).
No. It is not at all run on bootup.
It is run by an hourly cron job as I wrote, see /etc/cron.hourly/.
And it does not “image” anything, it creates snapshots which is something completely different.
And it does not snapshot the whole root (/). There’s a reason why there are that many subvolumes in a default installation…
Not running on a timer unless you create a custom policy to do so.
And, can create an image manually on demand if desired.
The default is to create a snapshot every hour.
Been looking at this for the past week…
Well, I have no idea at what exactly you have been looking. But probably not on the default openSUSE snapper config… 