TTG CE3 Gallery 5.2.0 and newer automatically creates cart templates in a similar way to the creation of Publisher templates. By setting these up, you can customise the appearance of the cart page (e.g. http://yoursite.com/cart) to be consistent with the appearance of your galleries.
To use an exported Gallery as a template:
Note: In setting up templates in this way, the URL to the template serves only as a template, and can not function as a cart-enabled gallery.