A new beta feature will soon be released on all wikis: The FileExporter. It allows exports of files from a local wiki to Wikimedia Commons, including their file history and page history. Which files can be exported is defined by each wiki's community: Please check your wiki's configuration file if you want to use this feature.
The FileExporter has already been a beta feature on mediawiki.org, meta.wikimedia, deWP, faWP, arWP, koWP and on wikisource.org. After some functionality was added, it's now becoming a beta feature on all wikis. Deployment is planned for January 16. More information can be found on the project page.
You will not be able to edit the wikis for up to 30 minutes on 17 January 07:00 UTC. This is because of a database problem that has to be fixed immediately. You can still read the wikis. Some wikis are not affected. They don't get this message. You can see which wikis are not affected on this page. Most wikis are affected. The time you can not edit might be shorter than 30 minutes. /Johan (WMF)