def parse_reference(reference):
    """
    parse provided image reference into <image_repository>:<tag>

    :param reference: str, e.g. (registry.fedoraproject.org/fedora:27)
    :return: collection (tuple or list), ("registry.fedoraproject.org/fedora", "27")
    """
    if ":" in reference:
        im, tag = reference.rsplit(":", 1)
        if "/" in tag:
            # this is case when there is port in the registry URI
            return reference, "latest"
        else:
            return im, tag

    else:
        return reference, "latest"