With this modification you can allow users to upload a profile image that will be placed in their details page.

1. Create a folder called uploads in the same folder as submit.php (root of the directory)
2. chmod 777 uploads
3. create a file image_upload.php in the same folder as submit.php, with the content below:

<?php 

$error=$_FILES["IMAGE"]["error"];
if ($error == UPLOAD_ERR_OK) {
 $parsed = parse_url($_POST["URL"]);
 $image_domain = $parsed['host'];
 $image_type=$_FILES['IMAGE']['type'];
 $image_loc="uploads/".$image_domain.".jpg";
 $tmp_name = $_FILES["IMAGE"]["tmp_name"];
  if ($image_type =="image/pjpeg" ||
      $image_type =="image/jpeg" ||
      $image_type=="image/gif"    ||
      $image_type=="image/png"){ 
    move_uploaded_file($tmp_name, $image_loc);
  }	
}

?>

4. in submit.php,
AFTER: require_once 'init.php';
ADD: require_once "image_upload.php";

5. in submit.tpl

FIND : 

<form action="" method="post">

REPLACE BY: 

<form action="" method="post"
          enctype="multipart/form-data">

FIND: 

<td class="field">
      {* Load category selection *}
      {include file="category_select.tpl"}
   </td>
   </tr>

AFTER it, ADD:

<tr>
 <td class="label">Image</td>
 <td class="field">
  <input type="file" name="IMAGE" />
 </td>
</tr>

7. in detail.tpl, where you want the image to appear.
ADD: 

{php}
$uploads_path="/path/to/uploads/";
$parsed = parse_url($this->_tpl_vars[URL]);
$image_domain = $parsed['host'];
$abs_image_loc = $uploads_path.$image_domain.".jpg";
$image_loc = "../uploads/".$image_domain.".jpg";
if (file_exists($abs_image_loc)) {
  echo "<img src=\"" . $image_loc . "\" />";
}
{/php}

EDIT : $uploads_path=”/path/to/uploads/”;
in the code above to something to the absolute path
to your uploads folder something like
“/home/domain/public_html/uploads/”

That’s it.
The mod can be improved by adding small test on the image size and dimensions.