public function fieldFilterValueLogo($object)
{
    global $conf;

    $dir = $conf->societe->multidir_output[$object->entity];
    $logoPath = $dir . "/" . $object->id . "/logos/" . $object->logo;

    if (!file_exists($logoPath)) {
        return null;
    }

    $type = pathinfo($logoPath, PATHINFO_EXTENSION);
    $content = file_get_contents($logoPath);

    return 'data:image/' . $type . ';base64,' . base64_encode($content);
}