$db_con  = @new mysqli( 'localhost',  'root', '',  'ImgBox_db' );
$user_id = $_SESSION['user_id'];
$user_content_id = "SELECT COUNT(user_id) FROM content WHERE user_id = '$user_id'";
$count  =  mysqli_query( $db_con,  $user_content_id );

$count=$dbh->query("SELECT COUNT(user_id) FROM content WHERE user_id = '$user_id'")->fetchColumn();

public function connectdb($db_name, $db_user, $db_pass, $db_host = "localhost")
{
    try {
        $this->db = new pdo("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
    } catch (pdoexception $e) {
        echo "database error: " . $e->getmessage();
        die();
    }
    $this->db->query('set names utf8');

    return $this;
}