Images:
Images are not backed up. You should make a backup of these images yourself or practice infrastructure as code and be able to easily recreate them if need be.
Volumes:
To backup a volume you’ll need to flag it for archive. The following script will help:
#!/bin/bash
export OS_CLOUD=<cloud name>
/usr/bin/openstack server set --property archive=true $1
Run script:
$ archive_flag.sh <instance name or id>