'Retrieves an image of the type specified from indexer and saves it to the cache folder
:param show_obj: TVShow object that we want to cache an image for
:param img_type: BANNER or POSTER or FANART
:return: bool representing success'

def _cache_image_from_indexer(self, show_obj, img_type):

    if (img_type == self.POSTER):
        img_type_name = u'poster'
        dest_path = self.poster_path(show_obj.indexerid)
    elif (img_type == self.BANNER):
        img_type_name = u'series'
        dest_path = self.banner_path(show_obj.indexerid)
    elif (img_type == self.POSTER_THUMB):
        img_type_name = u'poster_thumb'
        dest_path = self.poster_thumb_path(show_obj.indexerid)
    elif (img_type == self.BANNER_THUMB):
        img_type_name = u'series_thumb'
        dest_path = self.banner_thumb_path(show_obj.indexerid)
    elif (img_type == self.FANART):
        img_type_name = u'fanart'
        dest_path = self.fanart_path(show_obj.indexerid)
    else:
        sickrage.srCore.srLogger.error((u'Invalid    cache    image    type:    ' + str(img_type)))
        return False
    metadata_generator = GenericMetadata()
    img_data = metadata_generator._retrieve_show_image(img_type_name, show_obj)
    result = metadata_generator._write_image(img_data, dest_path)
    return result
