over the past 1,5 years WMDE’s Technical Wishes team has been working on a new functionality that allows to transfer files from a local wiki to Wikimedia Commons, while keeping all original data intact and documenting the move in the version history. 
The new functionality has been implemented via two extensions: FileImporter and FileExporter.  
We’re happy to announce that the new feature set can be tried out as a beta feature on first wikis as of today! 
Why this feature
This is why we developed the FileImporter/FileExporter extensions.
On a side note: The way the features are built, they theoretically could be used for transferring files from any mediawiki wiki to another mediawiki wiki in the future (the different wikis don't even have to be part of the same wikifarm).
However, our focus for now is:
Transfer of files from local wikis to Wikimedia Commons
To make use of the FileImporter, you have to activate the FileExporter in your local wiki, provided as a beta feature on Arabic Wikipedia, German Wikipedia, Persian Wikipedia and Mediawiki.org for now. The FileImporter on Wikimedia Commons is not a beta feature, so there is no need to activate it. 
If your local wiki community is interested to test the new functionality in this first round as well, please discuss this with your community and let us know by filing a request ticket on Phabricator :-) (example ticket: https://phabricator.wikimedia.org/T196908)
Last but not least, we’d like to thank all the people who have tested the feature earlier, and who have provided valuable feedback. This is much appreciated!
Further feedback is very welcome on the central feedback page: https://www.mediawiki.org/wiki/Help_talk:Extension:FileImporter
Birgit (for the Technical Wishes Team)
 https://www.mediawiki.org/wiki/Extension:FileImporter/Data, please note that any updates to these files will be used by FileImporter only by next week!
 https://www.mediawiki.org/wiki/Help:Extension:FileImporter (central help page)