Whether you're an author designing your own DIY book cover or a graphic designer on a tight budget designing an ebook cover for someone else it is always best to make sure that any image, vector, or illustration you get online is commercial free, and won't violate any copyrights or else you might get you sued for thousands of dollars.
If you are looking for the best websites to use commercial use stock images, vectors, or illustrations on your book cover designs for free then keep on reading. I'll also show you examples of book covers created with images from each specific site.