func ValidateImageName(image string) error {
	if len(image) == 0 {
		return nil
	}

	var err error
	if !refRegexp.MatchString(image) {
		err = errors.Errorf("Invalid image %s", image)
	}
	return err
}
func ValidateImageName(image string) error {
	if len(image) == 0 {
		return nil
	}

	var err error
	if !refRegexp.MatchString(image) {
		err = errors.Errorf("Invalid image %s", image)
	}
	return err
}
// ValidateImageName returns nil if the image name is empty or matches the open-containers image name specs.
// In any other case an error is returned.