Products not full size

-- url of the page with the problem -- : www.gitzone.co.uk/index.php/current-stoc...er-green-multidrawer
-- HikaShop version -- : 2.2.0
-- Joomla version -- : 2.5.17
-- PHP version -- : 5.3.27
-- Browser(s) name and version -- : Firefox V26
-- Error-message(debug-mod must be tuned on) -- : No Error Message

We I view a number of products (including the page highlighted) I can see the thumbnail OK, but when I click on the image it doesn't display the full size.

This file in definitely 768x1024, yet it display the same size as the thumbnail.

This seems such a basic function I must have done something wrong.

Best Regards

Jon