Free stock photos are available online through websites such as FreeStockPhotos.com, FreeDigitalPhotos.net and Unsplash as of 2015. Each site has its own policy on licensing, and some photos have specific stipulations that prevent them from being used for commercial purposes.
FreeStockPhotos.com requires users to keep the site's watermark on the downloaded images or credit the site somewhere else. Personal and commercial use is permitted, but each user is restricted to 10 images. Organizations that need more can contact the site's onwer to discuss a pricing plan.
FreeDigitalPhotos.net is a large site with a huge variety of images available at various resolutions. The smallest resolution is usually available for free, as long as proper credit is given. To obtain an image without credit or in a larger resolution, users must purchase an image. The images do not have a watermark. All of the photos are protected by a standard license that permits unlimited use of the image, but some situations may require purchasing an extended license through FreeDigitalPhotos.net.
Unlike the others, Unsplash does not host a large archive of photos. Subscribers receive 10 photos every 10 days for free. The photos are covered under a Creative Commons license that permits unrestricted use. The site does not require attribution.