Wikimedia Commons (or simply Commons) is an online repository of images, sound and other multimedia files. It is a project of the Wikimedia Foundation, from which uploaded files can be used across all Wikimedia projects in all languages, including Wikipedia, Wikibooks, Wikisource and Wikinews, or downloaded for offsite use. The repository contains over 5 million media files.

History

The project was proposed by Erik Möller in March 2004 and launched on September 7, 2004, A key motivation behind the setup of a central repository was the desire to reduce duplication of effort across the Wikimedia projects and languages, as the same file had to be uploaded to many different wikis separately before Commons was created.

Policies

Given its primary function as a supporting project for the other Wikimedia web sites, the main content policy for files uploaded to Commons is that they must be potentially useful on any of the Wikimedia projects. This excludes material such as purely personal pictures and artwork, in contrast to image sharing repositories like Flickr, Photobucket and DeviantArt. Nevertheless, large numbers of files hosted on Commons are not used directly on any Wikimedia project and likely never will be; as such, the project has grown into a repository of multimedia in its own right, which is frequently linked to from articles on Wikipedia and other Wikimedia websites to provide supplemental materials.

Most Wikimedia projects still allow local uploads which are not visible to other projects or languages, but this option is meant to be used primarily for material which local project policies allow, but which would not be permitted according to the copyright policy of Commons, such as fair use content. Wikimedia Commons itself does not allow fair use or uploads under non-free licenses, including licenses which restrict commercial use of materials or disallow derivative works. Licenses that are acceptable include the GNU Free Documentation License, Creative Commons Attribution and Attribution/ShareAlike licenses, other free content and free software licenses, and the public domain.

The default language for Commons is English, but registered users can customize their interface to use any other available user interface translations. Many content pages, in particular policy pages and portals, have also been translated into various languages. Files on Wikimedia Commons are categorized using MediaWiki's category system. In addition, they are often collected on individual topical gallery pages. While the project was originally proposed to also contain free text files, these continue to be hosted on a sister project, Wikisource.

Utilities

Over time, additional functionality has been developed to interface Wikimedia Commons with the other Wikimedia projects. Daniel Kinzler wrote applications for finding appropriate categories for uploaded files ("CommonSense"), determining the usage of files across the Wikimedia projects ("CheckUsage"), locating images with missing copyright information ("UntaggedImages"), and relaying information about administrative actions such as deletions to the relevant wikis ("").

Specialized uploading tools and scripts such as "Commonist" have been created to simplify the process of uploading large numbers of files. In order to review free content photos uploaded to Flickr, users can participate in a collaborative external review process (""), which has resulted in more than 10,000 uploads to Commons.

Quality

The site has three mechanisms for recognizing quality works. One is known as "Featured pictures", where works are nominated and other community members vote to accept or reject the nomination. This process began in November 2004. Another process known as "Quality images" began in June 2006, and has a simpler nomination process comparable to "Featured pictures". "Quality images" only accepts works created by Wikimedia users, whereas "Featured pictures" additionally accepts nominations of works by third parties such as NASA. A third image assessment project, known as "Valued images", began on June 1, 2008 with the purpose of recognising "the most valued illustration of its kind", in contrast to the other two processes which assess images mainly on technical quality.

The site held its inaugural "Picture of the Year" competition, for "Picture of the Year 2006". All images that were made a Featured picture during 2006 were eligible, and voted on by eligible Wikimedia users during two rounds of voting. The winning picture was a picture of the Aurora Borealis over snowlands, taken by a member of the US Air Force. The practice has continued; to date, Wikimedia Commons has completed Picture of the Year Competitions for 2006, 2007, and 2008.

See also

• Creative Commons – a project providing a set of content licenses and a directory of works using them

• Internet Archive – an online collection of videos, documents and webpages

• Project Gutenberg – the largest freely accessible collection of documents (including books and sheet music)

• Ourmedia – a community media archive