Most photos and images on the internet have a copyright. That means that you must get permission to use them.
Here is a list of websites that offer photos that are feee from copyright. The special term is public domain. This means anyone can use, change and distribute without getting permission or giving credit. Another term for this is Creative Commons Zero (CC0) license.
BE CAREFUL: Many of these websites have advertisements for images that are not free.
pixabay.com This is a huge and growing collection of high quality images. Most images have a high resilution version.
pexels.com Similar to pixabay.com
publicdomainpictures.net Good, but watch for ads.
http://www.picdrome.com/page/gallery Good, but watch for ads.
http://pdtextures.blogspot.ca good ba
list of lists