'Should return a dict like:
result = {<season number>:
{1: \'<url 1>\', 2: <url 2>, ...},}'

@staticmethod
def _retrieve_season_banner_image(show_obj, season, which=0):

    indexer_lang = (show_obj.lang or sickrage.srCore.srConfig.INDEXER_DEFAULT_LANGUAGE)
    try:
        lINDEXER_API_PARMS = srIndexerApi(show_obj.indexer).api_params.copy()
        lINDEXER_API_PARMS[u'language'] = indexer_lang
        t = srIndexerApi(show_obj.indexer).indexer(**lINDEXER_API_PARMS)
        indexer_show_obj = t[show_obj.indexerid]
        try:
            return indexer_show_obj[u'_images'][u'seasonwide'][season][u'filename'][which]
        except KeyError:
            pass
    except (indexer_error, IOError) as e:
        sickrage.srCore.srLogger.warning(((u'{}:    Unable    to    look    up    show    on    '.format(show_obj.indexerid) + srIndexerApi(show_obj.indexer).name) + u',    not    downloading    images:    {}'.format(e.message)))
        sickrage.srCore.srLogger.debug(((u'Indexer    ' + srIndexerApi(show_obj.indexer).name) + u'    maybe    experiencing    some    problems.    Try    again    later'))
