As I understand, the image is sourced through this: product.featured_image | img_url: 'master' but what would the img_url be for let's say an alternative.
You can access the product image array like so: product.images[1] | img_url: 'master', product.images[2] | img_url: 'master' etc. So 1 in that case would be the second image. Or you can create a separate metafield for that image if you dont want it in the image array :)
