Huge list of stock image sites that you can use on your website. Just be sure to check rights use. I’m a fan of a few sites listed here. Especially Pixabay and Unsplash because most of their photos don’t look like stock photos.
If you want great looking images that don’t look like stock photos, also check out http://www.stocksy.com. While not free, their photos look amazing. They great to use on product sales pages.