The image browsing prototype will probably be developed as a MW ResourceModule (CSS/JS code) as opposed to something that lives in the markup that is generated by the Wikitext parser. A future production version of this feature might need to be present in the server-rendered markup as well, but that is out-of-scope for now. We need to add this content to the page for participating users on the client-side.

This task assumes that one of the "entry points" in the design exists within the regular article page (i.e. not just embedded in MultimediaViewer, etc).

Acceptance Criteria

• Participating users (meaning: anon users included in the "experiment" group of a running A/B test, as well as any other users who have explicitly "opted in" via URL params or user prefs) are shown the Image Browsing UI when the page loads in their browser
• The loading experience is smooth (avoid sudden layout shifts, lengthy delays, etc)
• Non-participating users see no difference and have no noticeable performance impact