Prestashop error fix - quick job

I need someone good at prestashop to fix one error on a site (will be v quick). The problem is on product customisation. The first product customisation (image upload) works fine, but when this is added to the cart and try to create a second product customisation, the image thumbnail gets hidden. It still works however. steps to recreate: 1. go to [login to view URL] 2. upload an image 3. press upload 4. add to cart 5. upload another image Now it will be visible for a second then it gets hidden. If you delete the existing image in the cart, it will become visible.