Multimedia content in the form of animations, audio, images, and videos can help readers understand a concept in ways text alone cannot. To this end, Wikipedia hosts over 850,000 files for use in its articles.
Public domain or Creative Commons-licensed files should be uploaded to Wikipedia's sister project Wikimedia Commons, a multimedia file repository. Non-free content, like logos and album covers must be uploaded to Wikipedia itself, and then only for use if justifiable as "fair use" under U.S. copyright law.
There are several WikiProjects dedicated to multimedia, including WikiProject Spoken Wikipedia, which produces "audiobook" versions of Wikipedia articles, and WikiProject Wiki Makes Video, which aims to add more video content. Currently, only 0.1% of English Wikipedia's 5 million articles have video.