Protect photos (product) from downloading

I want to sell downloadable photos on my WooCommerce site. I have figured out how to add a watermark to the product image but clicking that image takes the user to the full-sized image in the WP media gallery. I still have a ways to go but here is my test site, click on the product image and you will get the full image. Any suggestions to protect my images? https://goodguygift.com/product/nyc-intersection/