Each product listing includes one primary product photo called the Main image.
A small thumbnail version of the Main image is shown for each listing in the results for Amazon’s search engine.
Product Listing Pages
Additional photos are available in an image gallery on the listing advertisement. The image gallery can contain multiple photos so long as they depict other sides, features or details that are not visible in the Main image. These photos are larger than the thumbnail found in the search results page. The listing advertisement has a built in zoom option that allows shoppers to see details of the item up-close (the level of detail is dependent on the resolution of the images).
Photos are normally uploaded when a new product listing is created. Merchants offering inventory for existing product listings are not require to submit new photos, however any merchant can add additional images to the product listing so long as they meet Amazon product image requirements.