No image checkbox on Diablo88s uploading script

How can I expand Diablo84`s nice script on uploading files with a checkbox that let users
choose a default image if they have no image to upload.Something like:



if ((empty($file_name)) and (empty($no_image)))
{
  $error[] = "No file has been selected";
}



I have placed a default.jpg image in the uploadfolder.


-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

<?php
if(array_key_exists('submit',$_POST)) {

 $allowed_files = array('image/gif','image/pjpeg','image/jpeg','image/jpg','image/png');
 $file_max = 51200; //1mb = 1048576 | 512kb = 524288 | 50kb = 51200
 $upload_path = $_SERVER['DOCUMENT_ROOT']."/pictures/"; //upload folder - make sure this folder has write permission!!!!!

 $file_name = $_FILES['upload']['name'];  
 
 $error = array();

 if (empty($file_name)) {
  $error[] = "No file has been selected";
 }
 else {
  if (!in_array($_FILES['upload']['type'],$allowed_files)) $error[] = "File type is not allowed";
  if ($_FILES['upload']['size'] > $file_max) $error[] = "File size is too big";
  if (file_exists($upload_path.$file_name)) $error[] = "A file with this name already exists";
 }

 if (count($error) == 0) {
  move_uploaded_file($_FILES['upload']['tmp_name'], $upload_path.$file_name) or die("Error Completing Request");
  echo "File Upload Complete<br>";
 }
 else {
  echo "The following errors occured\n<br>";
  foreach ($error as $var) echo " - $var<br>\n";  
 }

}
?>

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="uploadfile" enctype="multipart/form-data">
<input name="upload" type="file" size="40">
<input name="submit" type="submit" value="Upload">

===========-------------------------===============================

<input name=\"no_image\" type=\"checkbox\" value=\"default.jpg\">

=============-----------------------=================================


</form>




$fb = $_FILES['upload']['name'];
$fb = $no_image;
$db->sql_query("INSERT INTO far VALUES (NULL,'$username','$fb','$f1','$f2')");


And if the user activate the checkbox this will change the insert query to $fb = $no_image

Or do you have a better solution?