| For example, if we want to deploy using a full Pithos URI:
| ``img_id=pithos://<user-uuid>/<container>/<slackware-image>``
| or if we already know the map:
- | ``img_id=pithosmap://<slackware-image-map-name>``
+ | ``img_id=pithosmap://<slackware-image-map-name>/<size>``
* **Null back-end**:
To select the Null back-end and skip the fetching and extraction step, we set