python-novaclient allows an image to be specified to rescue with, however the "openstack server rescue" command does not.

$ nova help rescue

usage: nova rescue [--password <password>] [--image <image>] <server>

Reboots a server into rescue mode, which starts the machine from either the
initial image or a specified image, attaching the current boot disk as
secondary.

Positional arguments:
  <server> Name or ID of server.

Optional arguments:
  --password <password> The admin password to be set in the rescue
                            environment .
  --image <image> The image to rescue with.