private function _uploadImage()
    {
        $config['upload_path']          = './upload/service/';
        $config['allowed_types']        = 'gif|jpg|png';
        $config['file_name']            = $this->service_id;
        $config['overwrite']            = true;
        $config['max_size']             = 1024; // 1MB
        // $config['max_width']            = 1024;
        // $config['max_height']           = 768;

        $this->load->library('upload', $config);

        if ($this->upload->do_upload('image')) {
            return $this->upload->data("file_name");
        }

        return "default.jpg";
    }