Product variation pictures not showing up

I want the main product picture to change when selecting a variation. I can add pictures for the variations but they do not change the main picture when the variation is selected and sometimes the main picture does not show up. This should be a minor adjustment. It is probably something I don’t have set right. I need someone that can fix the problem or tell me what I am doing wrong. Here is an example of what I am talking about --[login to view URL] I need this fixed as soon as possible. The other products will have 6 or 7 variations each. Please do not bid before you read the project and look at the example.