The WIkimedia Foundation announced that on December 4, Wikimedia Commons, the organization’s free media repository, hit a 15 million media file milestone. There are now over 15 million pictures, videos and audio files, and the 15 millionth one shows Tropical Depression Seventeen-W, described as a “tropical cyclone that developed during the 1996 Pacific typhoon season.” It comes from the U.S. National Oceanic and Atmospheric Administration.

The last such milestone the foundation announced was 10 million media files, back in April of 2011.

“Credit is due to the Wikimedia Commons community, who is largely involved in a variety of projects, processes and negotiations that are intended to improve the availability of public domain and freely-licensed educational media content to the public,” says Peter Weis on the Wikimedia blog.

“The last two years have seen an increasing number of cultural institutions (GLAM) and other organisations providing content that would have otherwise not been freely accessible,” he adds. “Two Wiki Loves Monuments contests have also been responsible for more than 500,000 uploaded images. Moreover, constant technical improvements, such as the UploadWizard introduced in May 2011, and the new HTML5 video player, facilitate the contributions of current and future participants and encourage them to expand niches like audio and video.”

Wikimedia projects attract 480 million unique visitors per month, according to the foundation.