def get_base_output_name(filename_dict):
    """Returns the base output name used for preview images and
    thumbnails.

    Parameters
    ----------
    filename_dict : dict
        A dictionary containing parsed filename parts via
        ``filename_parser``

    Returns
    -------
    base_output_name : str
        The base output name, e.g. ``jw96090001002_03101_00001_nrca2_rate``
    """

    base_output_name = 'jw{}{}{}_{}{}{}_{}_'.format(
        filename_dict['program_id'], filename_dict['observation'],
        filename_dict['visit'], filename_dict['visit_group'],
        filename_dict['parallel_seq_id'], filename_dict['activity'],
        filename_dict['exposure_id'])

    return base_output_name