GWToolset (or GLAMWikiToolset) is a Special Page extension. The main goal of the extension is to allow GLAMs the ability to mass upload content (pictures, videos, and sounds) to Wikimedia Commons based on respective metadata (XML); the intent is to allow for a wide variety of XML schemas. The extension goes about this task by presenting the user with several steps, represented by HTML forms, in order to set-up a batch upload process that will upload content and metadata to the wiki, which creates individual mediafile pages for each item uploaded.
Further information can be found on the project page. Your feedback and questions are welcome, feel free to contact us.