I am trying to build an email tracker based on the folder name that requests the image.

Example:

`https://www.example.com/image/123/spager.gif`

which need to be turned into this

`https://www.example.com/image/index.php?id=123`

which in return would serve the spacer.gif image.

Is this doable? And if yes, what am I missing?

So fare I got this:

web.config:

```
<rule name="email image tracker">
  <match url="^/image/([0-9]+)/spacer.gif">
  <action type="Rewrite" url="/image/index.php?id={R:1}" />
</rule> 

```

index.php:

```
<?php
  header('Content-type: image/gif');
  $png_image = imagecreate(150, 150);
  imagecolorallocate($png_image, 15, 142, 210);
?>

```

but I am getting the error:

> 
> The page cannot be displayed because an internal server error has occurred.
> 
> 
> 

and nothing in the log files that would help me get a hint on what is not working.