Image problem on variable products

Ok, this is gonna be a hard one to explain.
Generally speaking the problem is on woocommerce, products of the variable type.

Lets say i have a product. A t-shirt i 3 colors, red,green and blue.
I create a product and gives this 3 variations based on my attributes.
On the 3 atrtibutes products i add pictures. I save my product and i open the page.
Now each time i choose another color, the picture changes to the correct picture.
That is all very very fine. All is working well.

Problem is that on the index-pages (like /shop ) my product has no image. Since i did not set any default image on the product, WordPress has no iamge to show. I thouhgt that if for example i set the blue product to be the default product, the index pages would show the blue image. But it does not.
So the i went and added a default product image (bottom right) all would be fine. But if i do that, the effect of changing images based on attribute dissapears or stops working.

Kind of hard to explain, but i hope you undestand.

Is there a fix?