@classmethod
def exists(cls, client, fingerprint, alias=False):
    """Determine whether an image exists.

        If `alias` is True, look up the image by its alias,
        rather than its fingerprint.
        """
    try:
        if alias:
            client.images.get_by_alias(fingerprint)
        else:
            client.images.get(fingerprint)
        return True
    except cls.NotFound:
        return False
