'Create an image of the original server.
For a full list of available parameters, please refer to the official
API reference:
https://developer.openstack.org/api-ref/compute/#create-image-createimage-action'

def create_image(self, server_id, **kwargs):

    post_body = {'createImage': kwargs}
    post_body = json.dumps(post_body)
    (resp, body) = self.post(('servers/%s/action' % server_id), post_body)
    self.validate_response(schema.create_image, resp, body)
    return rest_client.ResponseBody(resp, body)
