How to remove Prestashop useless images at img/p/

At Prestashop when I remove some products, the images remains at their directory /img/p/ so at the moment my images directory it's close to being 2GB. Found this script to delete useless and BBDD unlinked images on Prestashop but I don't know why It's only detecting the orphan images but not removing them. Maybe the unlink function is disabled on the php configuration? Is it possible? Or the code is wrong? Is there another way to do this kind of cleanup?

    <?php
// root path of the shop
$shop_root='/home/myweb/public_html/';
// limit number of image files to check, set to 10 for testing
$limit=1000000000;


include $shop_root . '/config/settings.inc.php';
$pdo = new PDO( 'mysql:host='._DB_SERVER_.';dbname='._DB_NAME_, _DB_USER_, _DB_PASSWD_ );
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$r=$pdo->query('select count(1) cnt from ps_image')->fetch();
echo 'count images database: '.$r['cnt'] . "<Br />";

// reset some counters
$cnt_files=0;
$cnt_checked=0;
$cnt_not_found=0;
$cnt_found=0;

for($ii=1; ($ii<=9) && ($cnt_files != $limit); $ii++)
{
        $path=$shop_root.'img/p/'.$ii;
        delImage($path);
        for($jj=0; ($jj<=9) && ($cnt_files != $limit); $jj++)
        {       
                $path=$shop_root.'img/p/'.$ii.'/'.$jj;
                delImage($path);
                for($kk=0; ($kk<=9) && ($cnt_files != $limit); $kk++)
                {
                        $path=$shop_root.'img/p/'.$ii.'/'.$jj.'/'.$kk;
                        delImage($path);
                        for($ll=0; ($ll<=9) && ($cnt_files != $limit); $ll++)
                        {
                                $path=$shop_root.'img/p/'.$ii.'/'.$jj.'/'.$kk.'/'.$ll;
                                delImage($path);
                        }       
                }
        }

}
echo 'files: '.$cnt_files.' checked: '.$cnt_checked.' not_found: '.$cnt_not_found.' found: '.$cnt_found;

function delImage($imageDir)
{
        global $limit, $pdo, $cnt_files, $cnt_checked, $cnt_not_found, $cnt_found;
        if ($handle = @opendir($imageDir)) {                    //@ is wriiten to avoid warning message and is handled in else condition
                echo $imageDir."<BR />";
                while ($cnt_files != $limit && false !== ($entry = readdir($handle))) {
                        if ($entry != "." && $entry != "..") {
                                $cnt_files++;
                                $pi = explode('-',$entry);
                                if($pi[0]>0 && !empty($pi[1])) {
                                        $cnt_checked++;
                                        if(!checkExistsDb($pdo,$pi[0])) {
                                                $cnt_not_found++;
                                                echo 'rm '.$imageDir.'/'.$entry."<BR />";
                                                unlink($imageDir.'/'.$entry);
                                        } else {
                                                $cnt_found++;
                                        }
                                }
                        }
                }
                        closedir($handle);
  }
        else
        {
                echo $imageDir." doesn't exist".'<BR />';
        }

}

function checkExistsDb($pdo, $id_image) {
        $r=$pdo->query($q='select 'ok' ok, (select id_image from ps_image where id_image = '.(int)$id_image.') id_image');
        $row=$r->fetch();
        if($row['ok']!='ok') die( 'Problem with query, please correct');
        return $row['id_image']?true:false;
}
?>

Here's an output piece:

/home/myweb/public_html/img/p/9/9/7
/home/myweb/public_html/img/p/9/9/7/0 doesn't exist
/home/myweb/public_html/img/p/9/9/7/1 doesn't exist
/home/myweb/public_html/img/p/9/9/7/2 doesn't exist
/home/myweb/public_html/img/p/9/9/7/3 doesn't exist
/home/myweb/public_html/img/p/9/9/7/4 doesn't exist
/home/myweb/public_html/img/p/9/9/7/5 doesn't exist
/home/myweb/public_html/img/p/9/9/7/6 doesn't exist
/home/myweb/public_html/img/p/9/9/7/7 doesn't exist
/home/myweb/public_html/img/p/9/9/7/8 doesn't exist
/home/myweb/public_html/img/p/9/9/7/9 doesn't exist
/home/myweb/public_html/img/p/9/9/8
/home/myweb/public_html/img/p/9/9/8/0 doesn't exist
/home/myweb/public_html/img/p/9/9/8/1 doesn't exist
/home/myweb/public_html/img/p/9/9/8/2 doesn't exist
/home/myweb/public_html/img/p/9/9/8/3 doesn't exist
/home/myweb/public_html/img/p/9/9/8/4 doesn't exist
/home/myweb/public_html/img/p/9/9/8/5 doesn't exist
/home/myweb/public_html/img/p/9/9/8/6 doesn't exist
/home/myweb/public_html/img/p/9/9/8/7 doesn't exist
/home/myweb/public_html/img/p/9/9/8/8 doesn't exist
/home/myweb/public_html/img/p/9/9/8/9 doesn't exist
/home/myweb/public_html/img/p/9/9/9
/home/myweb/public_html/img/p/9/9/9/0 doesn't exist
/home/myweb/public_html/img/p/9/9/9/1 doesn't exist
/home/myweb/public_html/img/p/9/9/9/2 doesn't exist
/home/myweb/public_html/img/p/9/9/9/3 doesn't exist
/home/myweb/public_html/img/p/9/9/9/4 doesn't exist
/home/myweb/public_html/img/p/9/9/9/5 doesn't exist
/home/myweb/public_html/img/p/9/9/9/6 doesn't exist
/home/myweb/public_html/img/p/9/9/9/7 doesn't exist
/home/myweb/public_html/img/p/9/9/9/8 doesn't exist
/home/myweb/public_html/img/p/9/9/9/9 doesn't exist
files: 29013 checked: 22290 not_found: 0 found: 22290