checkout confirmation and Universal Email receipt issues

Hi Folks,

Can you help.
When a successful transaction goes through it takes me to the checkout_success.php page and shows an order number, however when the email receipt comes through, it is lacking the order number and images of the products purchased. If i hit the go back button and return to the confirm page and checkout, it sends the order number via e-mail this time, but again no images.
Also, in order to clear the cart contents, ive used the following below the closing </html> on the checkout_success.php page
<?php unset($_SESSION['stonehouse_OrderID']);
$stonehouse->ClearCart();
?>
Ive also removed the above code and again had a successful checkout, however it doesnt alter the fact that theres no images contained in the email, nor an order number.
Is there a better way to clear the cart contents than above and can you help diagnose the lack of images in the emails and lack of order numbers.

Best Regards

Paul