Right now on my Photopost gallery all my categories do not end in a / they are redirected once clicked. You can see this here: Ford Mustang Pictures - Mustang Evolution

For example this: http://www.mustangevolution.com/gallery/showphoto.php/photo/3584/cat/2 shows up on the page to be clicked but once clicked it shows this: http://www.mustangevolution.com/gallery/showphoto.php/photo/3584/cat/2/

How do I make it add the trailing slash on the page and not redirect?