[HELP] upload

[eluser]C_Line[/eluser]
i wan to upload a image

Code:

view
<input type = "file" name="file" id="file">

model
$config['upload_path'] = './uploads/';
$config['allowed_types'] = 'gif|jpg|png';
$config['max_size'] = '100';
$config['max_width']  = '1024';
$config['max_height']  = '768';

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

if ( ! $this->upload->do_upload())
{
$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);

how to do ?