Since it is successfully run by the Wikimedia Foundation on a large scale we can be assured that this is a solution that will scale up.
Including media from the Wikimedia Commons onto this wiki
SYNTAX: [[File:Name on Wikimedia Commons]] will include the media in the article.
Guides into Wikimedia Commons
How to add it to an another wiki
To include media from the Wikimedia Commons to your own wiki you must activate it in LocalSettings.php by setting
- http://www.mediawiki.org/wiki/Manual:$wgForeignFileRepos if you need to source media from many wikis or
- By setting $wgUseInstantCommons to true to use only the Wikimedia Commons as external image source