WORDPRESS : Add more page numbers in the navigation bar

I would like to add more pages numbers in the bottom of a Wordpress portfolio page. There are currently only 2 numbers, I would like to put 8 pages.

screenshot

The website is under maintenance and you need to login to see the pages. If you need more informations, don't hesitate to ask. If you know what to change, you are welcome.

I added parameters 'mid_size' => 4,

                            'show_all'           => true,

                            'end_size'           => 1,

in all $args but no effect :

$args = array(

                            'post_type'        => 'portfolio',

                            'showposts'        => $items_count,

                            'offset'           => $custom_count,

                            'suppress_filters' => $suppress_filters,

                            'mid_size'           => 4,

                            'show_all'           => true,

                            'end_size'           => 1,

                            );

Thank you very much !

---

The /portfolio-loop.php code :