In a cloud in which interoperable image import is enabled, the Image Create response will include a OpenStack-image-import-methods header listing the types of import methods available in that cloud. Alternatively, these methods may be determined independently of creating an image by making the Import Method Discovery call.

In a cloud in which multiple storage backends are available, the Image Create response will include a OpenStack-image-store-ids header listing the stores available in that cloud. Alternatively, these stores may be determined independently of creating an image by making the Stores Discovery call.

https://docs.openstack.org/api-ref/image/v2/#interoperable-image-import

https://github.com/openstack/glance/blob/stable/rocky/glance/api/v2/images.py#L961