func (f *fakeDockerRegistryClient) ImageByID(namespace, name, id string) (*docker.Image, error) {
	f.Namespace, f.Name, f.ID = namespace, name, id
	for _, t := range f.Images {
		if t.ID == id {
			return t.Image, t.Err
		}
	}
	return nil, dockerregistry.NewImageNotFoundError(fmt.Sprintf("%s/%s", namespace, name), id, "")
}
func (f *fakeDockerRegistryClient) ImageByTag(namespace, name, tag string) (*docker.Image, error) {
	if len(tag) == 0 {
		tag = api.DefaultImageTag
	}
	f.Namespace, f.Name, f.Tag = namespace, name, tag
	for _, t := range f.Images {
		if t.Tag == tag {
			return t.Image, t.Err
		}
	}
	return nil, dockerregistry.NewImageNotFoundError(fmt.Sprintf("%s/%s", namespace, name), tag, tag)
}