How can I pass the upload process if one of three fields of input files is not assigned any file

Hi, I used this library and it works great, except only one issue because i made a change in the view page and I want it to be like that I just changed the view file like that to make three fields separately to use it for my database just like that:

                    echo '<div class="form-group">';
                    echo '<label for="img"> Main image: </label>';
                    echo form_upload('uploadedimages[]','','multiple');
                    echo '</div>';

                    echo '<div class="form-group">';
                    echo '<label for="img"> Second Image: </label>';
                    echo form_upload('uploadedimages[]','','multiple');
                    echo '</div>';

                    echo '<div class="form-group">';
                    echo '<label for="img"> Third Image: </label>';
                    echo form_upload('uploadedimages[]','','multiple');
                    echo '</div>';

This way above when I select files on all of the fields and upload it, it works great. but if I don't select a file in any one of them the process fails and it says " there is no file selected" something like that.

and this is my controller:

       function do_upload()
      {
    //if save button was clicked, get the data sent via post
    if ($this->input->server('REQUEST_METHOD') === 'POST')
        {
        //form validation
        $this->form_validation->set_rules('name', 'name', 'required');
        $this->form_validation->set_rules('manufacturer', 'manufacturer name', 'numeric');
        $this->form_validation->set_rules('model', 'model name');
        $this->form_validation->set_rules('category', 'category', 'required');
        $this->form_validation->set_rules('price', 'price', 'required|numeric');
        $this->form_validation->set_rules('stock', 'stock', 'required');
        $this->form_validation->set_rules('description', 'description');
        $this->form_validation->set_error_delimiters('<div class="alert alert-error"><a class="close" data-dismiss="alert">×</a><strong>', '</strong></div>');
        //if the form has passed through the validation
        if ($this->form_validation->run())
        {

            $config['upload_path'] = './uploads/products/temp';
            $config['allowed_types'] = 'gif|jpg|png';
            $config['max_size'] = '12200';
            $config['max_width']  = '12024';
            $config['max_height']  = '7268';

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

            if ( ! $this->upload->do_upload('uploadedimages'))
            {
                $error = array('error' => $this->upload->display_errors());

                $error['main_content'] = 'pages/add_product';
                $this->load->view('templates/template', $error);
            }
            else
            {
                $data = array('upload_data' => $this->upload->data());

                $data_to_store = array(
                'name'              => $this->input->post('name'),
                'manufacturers_id'  => $this->input->post('manufacturer'),
                'model'             => $this->input->post('model'),
                'categories_id'     => $this->input->post('category'),
                'sell_price'        => $this->input->post('price'),
                'stock'             => $this->input->post('stock'),
                'used'              => $this->input->post('used'),
                'description'       => $this->input->post('description'),
                'img'               => $data['upload_data'][0]['full_path'],
                'img1'              => $data['upload_data'][1]['full_path'],
                'img2'              => $data['upload_data'][2]['full_path'],
                'product_date'      => date('Y-m-d H:i:s'),
                'seller_id'         => $this->session->userdata('user_id'),
                'uploader_ip'       => $this->input->ip_address(),
                );
                //if the insert has returned true then we show the flash message
                if($this->products_model->store_product($data_to_store) == TRUE){
                    $this->session->set_flashdata('flash_message', 'Uploaded');

                    $data['main_content'] = 'pages/add_product';
                    $this->load->view('templates/template', $data);
                }else{
                    $this->session->set_flashdata('flash_message', 'not_uploaded');
                }
            }

        }//validation run
        else{
            $data['main_content'] = 'pages/add_product';
            $this->load->view('templates/template', $data);
        }

    }
    else{
            redirect('home/user_add_product'); 
        }
}

avenirer / MY_Upload

How can I pass the upload process if one of three fields of input files is not assigned any file #2