The builtin SD Card Copier tool can create copies smaller than the system sd card, so it can be used for cloning the system into smaller cards. Is there a similar tool (running on any os) for creating small image files from an rpi system sd card?
As far as I understand dd and bkup_rpimage are copying the full system drive. There is an option to compress it after dumping but it will still require the same size target sd card when restoring.
UPDATE: I found RonR-RPi-image-utils (more than 1 version) and PiShrink scripts that should be able to do this. Others suggested using rsync. So far I have tested PiShrink on an image created by Win32DiskImager and it seems to work well.
I wonder if the shrunk images produced by those methods are fail-safe as the SD Card Copier results.