https://www.mediawiki.org/wiki/Help:VisualEditor/User_guide#Editing_media_galleries is out of date. It needs new screenshots to show off the awesome improvements to the interface.

VisualEditor is MediaWiki's rich-text editor. Find out more about VisualEditor here.
The MediaWiki software allows displaying several images together as a "gallery".

In the VisualEditor user guide, the screenshots for editing media galleries are outdated.

You must have played and understood VisualEditor a bit for this task, and you must have knowledge how to create screenshot images and edit them in an image manipulation application. Also see the guide on taking and using screenshots. Your updated screenshot images must be consistent with the style of the already existing images.

Go to the VisualEditor test page and use VisualEditor on that page in order to update the existing screenshots for editing media galleries. Those screenshots are hosted on https://commons.wikimedia.org/ and each screenshot file page on Commons offers a "Upload a new version of this file" link which is to be used.