'Return the ID for the specified image name or identifier.
:param image_identifier: image name or a UUID-like identifier
:returns: the id of the requested :image_identifier:
:raises: exception.EntityNotFound,
exception.PhysicalResourceNameAmbiguity'

def get_image_id(self, image_identifier):

    try:
        return self.find_resource_by_name_or_id('images', image_identifier)
    except exception.EntityNotFound:
        raise exception.EntityNotFound(entity='Image', name=image_identifier)
