How to get by api avu group VK?

Question

API

Guys, my code pulls out the link to the ava is not correct, how to fix the error?

public function FilterVkGroup($a) {
        if (!empty($a)) {
            if (preg_match("/^(http|https):\/\/(www.vk|vk).com\/([\.\-_a-zA-Z0-9]+)/i", $a)) {
                $url = parse_url($a);
                $path = $url['path'];
                preg_match_all('#(club|public)([0-9]+)#', $path, $name, PREG_SET_ORDER);
                if (!empty($name)) {
                    $groupid = $name[0][2];
                    $return_url = 'https://www.vk.com/'.$name[0][0];
                } else {
                    $groupid = substr($path,1);
                    $return_url = 'https://www.vk.com/'.$groupid;
                }
                $res = $this->url_get_contents('https://api.vk.com/method/groups.getById?&group_id='.$groupid.'&v=5.80&access_token='.$this->TokenVK);
                $resp = json_decode($res, true);
                if (isset($resp['response'])) {
                    if ($resp['response'][0]['is_closed'] == '0') {
                        return array('success', $return_url, $resp['response'][1]['photo_100'], 'Сообщество');
                    } else return array('error', 'Сообщество должно быть открытым для подписок!');
                } else return array('error', 'Сообщество не найдено, проверьте ссылку!');
            } else return array('error', 'Неверный формат ссылки!');
        } else return array('error', 'Вы не указали ссылку на задание!');
    }

It needs to be in this format

https://sun7-9.userapi.com//s//v1//ig2//1UP8qeZDTheOuq27ssDqHCI1-2D0YRd1O4TLj5oUOM_6WF_lKxarCvmb9iq3XYo3fLvJiB9CwvI0F9Dj74KQaw-z.jpg?size=100x0&quality=96&crop=0,0,639,639&ava=1

And he pulls like this

https://sun1-96.userapi.com/s/v1/ig2/SiFtS4aszJ4dzV_8HmmzsPJv1aSBXX5MJrliOcvpHotdgkmDYo8VB7QbUDVA0YImxybC85BOQ29GpxfBh4l_G67Q.jpg?size=200x0&quality=9