Extension:MultimediaViewer

The MultimediaViewer extension gives the user of a wiki a slightly nicer interface for viewing full-size, or nearly full-size, images in their browser without extraneous page loads or confusing interstitial pages.

Installation
First, ensure that Extension:BetaFeatures is installed. MultimediaViewer uses the GetBetaFeaturePreferences hook, which is created and run from BetaFeatures.

Setting up context for metadata
You might want to create a structure similar to what User:MarkTraceur has on his wiki, which is a barebones version of the Commons Information template system. You'll also likely want to download Extension:CommonsMetadata and the unmerged and, as well as unmerged  for core.

You should probably also add to the image in order to test some of the licensing functionality.

Using the extension
First thing, before testing, is to make sure you're logged in and you have the preference enabled: Log in to the wiki and go to Special:Preferences, then visit the "Beta features" tab and check the appropriate box.

Next, go to a page that has a thumbnail on it. Try clicking on the image or on the "expand" icon near it. The lightbox should pop up and give you a bigger view of the image.

If you'd prefer, there's an exported test environment that you can use via Special:Import to quickly set up a suitable testing environment.