How to get overlay image from upload form

[lamkute]

hi,
im trying to get overlay image from upload form with this code but it not work.
please help.
Thank you!

   <form method="post" enctype="multipart/form-data">
   <table>
   <tr>
   <td>Upload Image*</td>
   <td><input type="file" name="uploadfile" /></td>
   </tr>

   <tr>
   <td colspan="2">
    <small><em>* Acceptable image formats include: GIF, JPG/JPEG and PNG.
	</em></small>
   </td>
   </tr>

   <tr>
   <td colspan="2" style="text-align: center;">
    <input type="submit" name="submit" value="Upload"/>
  </td>
  </tr>
  </table>
  </form>

<?php
if(isset($_POST['submit'])){
require_once('../src/PHPImage.php');

$bg = './img/benji.jpg';
$overlay = $_FILES['uploadfile']['tmp_name'];
$image = new PHPImage();
$image->setDimensionsFromImage($bg);
$image->draw($bg);
$image->draw($overlay, '50%', '75%');
....
$image->show();
}
?>