Cara Membuat Form Upload Yang Bisa Me-resize Foto Dengan Ukuran Lebih Dari 1 Mb

Gimana sih buat form uplod foto yang bisa di resize jika file fotonya lebih dari 1 mb ? Script saya seperti ini

 public function do_insert()
	{
        $gbr            = $_FILES['foto']['name'];

        $config['upload_path'] = './assets/upload/fasilitas/';
        $config['allowed_types'] = 'jpg|png|jpeg';
        $config['encrypt_name'] = FALSE;

        $this->upload->initialize($config);
        if(!empty($_FILES['foto']['name'])){

            if ($this->upload->do_upload('foto')){
                $gbr = $this->upload->data();

                $config['image_library']='gd2';
                $config['source_image']= './assets/upload/fasilitas/'.$gbr['file_name'];
                $config['create_thumb']= FALSE;
                $config['maintain_ratio']= FALSE;
                $config['quality']= '50%';
                $config['width']= 600;
                $config['height']= 400;
                $config['new_image']= './assets/upload/fasilitas/'.$gbr['file_name'];
                $this->load->library('image_lib', $config);
                $this->image_lib->resize();
            }

                $data = array(
                  'nm_fasilitas'              	=> $this->input->post('nm_fasilitas'),
                  'isi_fasilitas'               => $this->input->post('isi_fasilitas'),
                  'tgl_upload'                  => date('Y-m-d'),
                  'id_user'                     => 1,
                  'foto_fasilitas'              => $gbr['file_name'],

                );

                $this->model_fasilitas->get_insert($data, 'tbl_fasilitas');
                $this->session->set_flashdata("info", "Data Berhasil Ditambah");
                redirect('fasilitas');

        }else if(empty($_FILES['foto']['name'])){
            if (!$this->upload->do_upload('foto')){}
            $key = $this->input->post('id_fasilitas');
            $query = $this->model_fasilitas->get_data($key);

            $data = array(
              'nm_fasilitas'                => $this->input->post('nm_fasilitas'),
              'isi_fasilitas'               => $this->input->post('isi_fasilitas'),
              'tgl_upload'                  => date('Y-m-d'),
              'id_user'                     => 1,

            );

            $this->model_fasilitas->get_insert($data, 'tbl_fasilitas');
            $this->session->set_flashdata("info", "Data Berhasil Ditambah");
            redirect('fasilitas');

        }else{
            $this->session->set_flashdata("pesan", "Data Gagal Ditambah");
            redirect('fasilitas');
        }
	}

Tapi ini hanya bisa mengupload file yang ukurannya kb aja, gimana ya supaya bisa baca yang ukuran mb terus diresize ?