We create a different product for each colour option of products (rather than use variants), which means oftentimes we're adding the same image to multiple products. In this case, where we've added the same image to multiple product pages, when a user views one product page (e.g. the green one) and then views another product page (e.g. the orange one) - are the images downloaded each time? Or does Shopify recognise that the images are the same and thus serve a now cached version of it?
Also, would adding images from a URL ensure that each image is only download once, thus likely improving page load speeds?