Some websites that offer free HD images include Unsplash.com, Gratisography.com and ReSplashed.com. All three websites offer images that users can use for commercial and personal projects.
As of 2015, Unsplash.com offers users 10 new free images every 10 days. Users can also submit their own HD images for other users of the site. The images at Gratisography.com are all taken by Ryan McGuire and are free of copyright restrictions. Some subjects include animals, nature, objects, people and urban landscapes. ReSplashed.com is a project by We Are Altitude, and all images are sourced by Crew. All images on the website fall under Creative Commons, and thus fall under public domain.