Getty Images, Wikimedia Commons, Pixabay, LibreShot.com and PublicPhoto.org offer free-to-use high definition pictures. In March 2014, Getty Images released over 35 million images for free online use, under the conditions that they are used for noncommercial purposes and accompanied by an attribution.
As of November 2015, Wikimedia Commons hosts over 29 million images, sound files and other media that are free to use. Pixabay holsts 480,000 free-to-use photos and cliparts. LibreShot.com hosts free-to-use high-resolution photos from Martin Vorel's photo blog. Vorel's blog contans photos from his travels through Mongolia, Thailand and Europe. PublicPhoto.org hosts over 26,000 free-to-use high definition photos.