You can use images from Amazon to sell Amazon products. They encourage it! I would stay away from customer images though.
Have a read of their TOS agreement. It specifically states:
"In order to facilitate your advertisement of Products, we may make available to you data, IMAGES, text, link formats, widgets, links...."
There's no need to attribute the images you get from Amazon either.
What you couldn't do is take their images and then sell the products through another merchant - does that make sense? If Amazon are profiting from sales then they are very happy for you to use the images.
If you want to use an additional image as well as the one that comes up automatically in the amazon capsule, go to the specific product. Right click on the largest product image (usually on the top left of the page). Click save image as. Save somewhere on your computer where you'll be able to find it easily. Then use an image capsule in your hub and upload the image.