We're sorry to say that Product Customizer options cannot adjust your product images, as image changing support is very tightly tied to Shopify variants. If you adjust your product variants, you'll notice that the URL changes -- Shopify changes the URL based on what variant is selected to let your theme know it should change the product image according.
Your theme must then also pick up on this signal, and get the right image to display. As this process requires:
a URL change on the Shopify side to indicate what image to use, and
your theme to pick up on this change and change the image accordingly,
there's not really a way for Product Customizer to insert itself into this process. It can't change the URL to indicate what image to display, and even if it could, your theme would then need to support this change to get and display the right image.
While adjusting images per option isn't technically feasible at present, we would love it if you'd let us know this is important to you! We have an idea board where we track popular feature requests, and our development team is always looking for new ways to solve problems like this in case it's something we can add to our app.
You can let us know here that option images are important to you :)