Abstract Influence (3456 px) requires registration in order to enter the site, but once you’re in, you can upload or download, and participate in the forum, all for free. Photos are grouped by category but there is no photo search function available.
Cepolina (1024 px) is an international Creative Commons site that offers collection browsing using maps of the world. You can also browse by category, or use a search function.
Creative Commons This website provides links to search engines that can be used to find images, video and audio that are not protected by copyright or allow manipulation under certain circumstances.
Everystockphoto: access to 4,479,046 free photos!
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, without advertising, and allows you to rate, tag, collect and comment on photos.
Dreamstime (3456 px) is a free Creative Commons source for stock photography. Registration required.
Flickr Commons Project
The Commons Project is a collection of medium and high resolution imagery contributed from archives around the world, including the US National Archives, OSU’s Archives, NYPL’s Archives, and many more. The photos contributed to this have no known copyright restrictions. Read more here. However, many of these images explicitly state they are for educational use only, and some state they may not be modified (ex: Smithsonian). Read the rights statement to be sure what you can and cannot do with these images before using them.
Freemediagoo was created for developers by developers. We provide a way for developers to gather assets that can be used in print, film, TV, Internet or any other type of media both for commercial and personal use.
Freepixels (2700 px) has a search function, categories, and a tag cloud to access a wide spectrum of stock photography.
Freerange (2400 px) offers a wide range of free stock photography, but requires registration before you can download.
GeekPhilosopher (800 px) is another source for royalty free stock photography, wallpapers, and desktop backgrounds. Browse images by a variety of collections.
Imageafter (3564 px) has 20,000 images available. There are two drop-down menus (one for textures, one for images) for category browsing. Imageafter allows you to use their images on printed material for resale.
Imagebase (3072 px) The photos on Imagebase are free to use, and are licensed under a Creative Commons license.
MorgueFile (very large) contains free high resolution digital stock photography for either corporate or public use. The term "morgue file" is popular in the newspaper business to describe the file that holds past issues flats. Although the term has been used by illustrators, comic book artist, designers and teachers as well. The purpose of this site is to provide free image reference material for use in all creative pursuits.
Openphoto (4200 px) Another free Creative Commons site with pictures accessed via category browsing or search engine.
Photo Rogue (2560 px) lets you request a picture of anything you want, and volunteer photographers might go out and attempt to actually take the picture you want. This is a great place to find free, large photographs of unusual subject matter.
Pixel Perfect Digital (3888 px) has a growing collection of images and textures. Registration allows you to upload to your own personal gallery. A search function allows searching within one or more category.
Public Domain Photos (2024 px) All photos on this web site are public domain. You may use these images for any purpose, including commercial. This site is especially helpful for finding photographs of nature.
Stockvault (4200 px) features thousands of images and some Photoshop tutorials. Membership is free and unlocks some additional features, such as a lightbox.
Stock.xchng (very large) SXC is a "friendly community of photography addicts who generously offer their works to the public free of charge."
Unprofound (1167 px) groups photographs by color, rather than category. There is also a search function.
Wikipedia Commons Images (very large) Images are available from 47 subcategories including 3D computer graphics, Advertisements, Illustrations and Maps.