User:Sage Ross (WMF)/commons

Wikimedia Commons, the free educational media repository used by Wikipedia and many other wikis, is for:
 * original works you made yourself (which you release under a Wikipedia-compatible free license)
 * works by others that were explicitly released under a Wikipedia-compatible license, or
 * works in the public domain that aren't covered by anyone's copyright.

If you are trying to illustrate a Wikipedia article, there are many ways to find freely licensed or public domain images and other media that can be added to Wikimedia Commons. Some of them are cataloged at Commons:Free media resources.

Commons may have the perfect image already. First, try some searches. But if you can't find what the article needs there, things get trickier. Public domain and freely licensed images are tucked away all over the internet, but you have to know where to look, and how to figure out whether an image really is okay for Wikimedia Commons.

Finding free images
When searching for free images, different subjects call for different strategies.

For anything that can be readily photographed (and where the subject itself is not a copyrighted work), Flickr is a good place to begin. Go to the Advanced Search page on Flickr and select " Only search within Creative Commons-licensed content" with both options: "Find content to use commercially" and "Find content to modify, adapt, or build upon". That will limit searches to the Wikipedia-compatible Creative Commons licenses (Attribution and Attribution-ShareAlike). A word of caution: be sure that any images you find like this appear to be the original work of the Flickr user who uploaded them, as opposed to found works or the works of others that are not legitimately released under the Creative Commons license.

High quality science-related images can often be found in freely licensed Open Access journals, such as Public Library of Science journals. Try searching Google Scholar for "PLoS" along with relevant search terms, and browsing the results for useful images. Some of the other sources of free images can be searched with the Creative Commons search tool. Use extreme caution, though, as results often include images of dubious provenance. In addition to the Creative Commons Attribution and Attribution-ShareAlike licenses, common Wikipedia-compatible licenses include the Free Art License, the GNU Free Documentation License (typically for software documentation), and the GNU General Public License or Lesser General Public License (typically for software screenshots).

Old works are often in the public domain. As a general rule, things published in the United States before 1923, or published works from outside the US whose authors died more than 70 years ago, are usually in the public domain. Works of the United States Federal Government, and some other governments, are also public domain. Some authors also release their works directly to the public domain, often using the CC0 rights waver. See Public domain for more on what is and is not in the public domain.

Uploading free images
When you've found an image that is pubic domain or has a Wikipedia-compatible free license, you should download it in the largest size available. Then, you can upload it to Wikimedia Commons the same way you would an original image. The key difference is in the "Release rights" step:
 * Select "This file is not my own work."
 * Enter the source of the image. This is typically the URL where you found the image.
 * Enter the author.
 * Select the appropriate free license or public domain situation for the image. The choices cover the most common cases, but if an image is definitely freely licensed or public domain but isn't covered by the choices, you can select "I found it on the Internet -- I'm not sure" and then find other images on Wikimedia Commons to identify the appropriate license or public domain template after the upload is complete.

Be sure to add a descriptive, concise title and a detailed description, and add the image to appropriate Wikimedia Commons categories, and make sure the "Date created" field corresponds to the actual date the work was created (rather than today's date, or the automatically-detected date the file was created, which may be different).

Examples
Examples of finding and adding an image from Flickr, PLoS