upload image file.

CI_Upload.php

<?php

/**
 * Created by PhpStorm.
 * User: vallabh
 * Date: 08/09/15
 * Time: 17:34
 */
class Test extends CI_Controller
{

    public function __construct()
    {
        parent::__construct();
        $this->load->helper(array('form', 'url'));
    }

    public function index()
    {
        $this->load->view('upload_form', array('error' => ' '));
    }

    public function do_upload()
    {
        $this->load->library('upload');
        if (!$this->upload->do_upload('userfile')) {
            $error = array('error' => $this->upload->display_errors());
            $this->load->view('upload_form', $error);
        } else {
            $data = array('upload_data' => $this->upload->data());
            $this->load->view('upload_success', $data);
        }
    }
}

?>