Pimcore\Model\Asset\Image\Thumbnail\Config::selectMedia PHP Method

    public function selectMedia($name)
    {
        if (array_key_exists($name, $this->medias)) {
            $this->setItems($this->medias[$name]);
            $suffix = strtolower($name);
            $suffix = preg_replace("/[^a-z\\-0-9]/", "-", $suffix);
            $suffix = trim($suffix, "-");
            $suffix = preg_replace("/[\\-]+/", "-", $suffix);
            $this->setFilenameSuffix($suffix);
            return true;
        }
        return false;
    }