PublicDomainPictures.net is a repository for free public domain images. Material can easily be browsed by various categories, including professional or seasonal photos. Image tags allow an easy search.
2- Wikimedia Commons
This is a database of 18,083,944 freely usable media files to which anyone can contribute. Media files can be surfed by topic, location, type, author, license, and source. Each of these categories has subcategories, to refine the search.
Pixabay is another great resource for high quality public domain pictures. You can register with pixaby and save yourself the trouble of having to type in captcha each you want to download a pic.
All photos on this web site are public domain. You may use these images for any purpose, including commercial.
The morguefile contains photographs freely contributed by many artists to be used in creative projects by visitors to the site.
ImageAfter is a large online free photo collection. You can download and use any image or texture from this site and use it in your own work, either personal or commercial.
This is a search engine for free photos. These come from many sources and are license-specific. You can view a photo’s license by clicking on the license icon, below and left of photos. Membership is free and allows you to rate, tag, collect and comment on photos.