So this is a nice little plugin – an add-on to Woocommerce called Smart Variation Images. The extension allows you to set different images to each product variation. This is handy to display different style types to the user as they browse through your product variation choices. Each time they select a new variation, the primary image changes. You set this up via the product gallery assigning each image to a variation label, or you can choose to set the images individually inside each option.
The real benefit to this extension is the fact that you can set multiple images to each variation. So even the gallery can be customized each option. Cool!
Check out the plugin and see for yourself.