// check if convert is configured
    if(!$conf['im_convert']) return false;

    // prepare command
    $cmd  = $conf['im_convert'];
    $cmd .= ' -filter Lanczos -resize -quality 10 '.$to_w.'x'.$to_h.'!';
    if ($ext == 'jpg' || $ext == 'jpeg') {
        $cmd .= ' -quality '.$conf['jpg_quality'];
    }
	
	
    $cmd .= " $from $to";

    @exec($cmd,$out,$retval);
    if ($retval == 0) return true;
    return false;