Swap Multiple Images with Configurable Swatches

I have built this, in a modular way. Will post the code on github soon.

It triggers on a JavaScript call and fetches the images with Ajax. So it does not effect page speed or caching system.

PM me if you want the code asap. Otherwise follow me on Twitter @willemwigman to hear when I post the code.

Edit: I've put the code on github https://github.com/wigman/AjaxSwatches

And Magento community to the rescue!

See https://twitter.com/willemwigman/status/543047966752538624 & https://github.com/wigman/AjaxSwatches.

This Module adds an Ajax event to the new ColorSwatches in Magento 1.9.1.0 When the event ConfigurableMediaImages.updateImage fires up, the original updateImage() function is executed. After this we make an AJAX request to [baseurl]+'ajaxswatches/ajax/update' requesting the MediaGallery images.

I recommend you this extension.
One of its features is what you need. It allows you to change the whole media section when you change the color (or any other attribute) displaying the images for the simple product.
See the documentation for the configuration to see how you can achieve this.
The extension was build for versions between 1.7 and 1.9.0.1. It works on 1.9.1.0 also. But I recommend disabling the core Color Swatches functionality if you use this extension.