public function urlBlankAvatar($iWidth = 100, $iHeight = 100, $sex = '')
    {
        if (!$this->isPermittedDimension($iWidth, $iHeight)) {
            throw new PermittedDimensionException(
                'CDN::urlBlankAvatar() - Transformation of image to ' . $iWidth . 'x' . $iHeight . ' is not permitted'
            );
        }

        // --------------------------------------------------------------------------

        return $this->callDriver('urlBlankAvatar', [$iWidth, $iHeight, $sex]);
    }