Images not loading consistantly

Im running the latest wordpress (3.2.1) with wp e-commerce plugin (3.7.8_ along with their gold cart plugin from getshopped.org

the main page of the store has a grid of 9 images and buy now buttons. Occasionally all 9 load but often only 3 or 7 or 5 of them load. If you refresh the page a different number of images load.

It is an inconsistent problem which makes it very hard to trouble shoot.

I have optimised the images and tried using some of the top cache plugins but to no resolve.

the page can be viewed here ->> crystaldelights.com/store **note it is adult content to a certain extent please do not view if under 18

Any ideas or input are appreciated as I’ve got nop clue as to how to solve it