wp e-commerce excluding categories from [showcategories]

I am using the latest version of wp e-commerce and am trying to have a grid of category images on the home page. However I wish to exclude a couple of the categories.

I know I can use [showcategories] shortcode to show all category images, but is there a way to define which are included?

Or maybe there is a better way altogether. I don’t mind hard coding the grid on the front page, but I would like the category images to be able to be changed in the admin panel.

The site is https://www.shop.dibbledog.com