docs: def get_image(conn, vm_):
      '''
      Return the image object to use
      '''
      vm_image = config.get_cloud_config_value('image', vm_, __opts__, default='').encode(
          'ascii', 'salt-cloud-force-ascii'
      )
      if not vm_image:
          log.debug('No image set, must be boot from volume')
          return None
  
      image_list = conn.image_list()
  
      for img in image_list:
          if vm_image in (image_list[img]['id'], img):
              return image_list[img]['id']
  
      try:
          image = conn.image_show(vm_image)
          return image['id']
      except novaclient.exceptions.NotFound as exc:
          raise SaltCloudNotFound(
              'The specified image, \'{0}\', could not be found: {1}'.format(
                  vm_image,
                  exc
              )
          )