We want to bring the MMV beta viewer () to feature parity with the existing MobileFrontend mobile image viewer. This is a prerequisite for replacing the current mobile viewer and rolling out the Image Browsing feature to production (T410786).

Context

The MobileFrontend mobile image viewer is a relatively simple lightbox experience. The feature set is small, which means the road to parity should be short. Once parity is reached, the MobileFrontend viewer code (ImageCarousel, ImageGateway, overlay factory, and related Minerva init code) can be retired. The beta viewer PoC (T417675) provides a starting point: basic image display, progressive loading, adjacent image prefetching, and the adapter interface for MMV's bootstrap. This epic covers everything else needed to match the current mobile viewer's functionality.

Potential Subtasks

Specific subtasks for feature parity should be documented here after T418334 is complete.

Other subtasks we may need need include:

• License info display (license short name, license link)
• Other metadata display (author, caption, file page link, metadata toggle)
• Download support at various sizes (see also T410952)
• Error handling for failed image loads
• Loading state / fallback indicator
• Image exclusion handling (noviewer, non-photographic content filtering)
• Detail view accessibility
• Instrumentation (product health metrics?)

Out of scope

• Touch gestures (pinch-to-zoom, swipe navigation) — potential fast-follow
• Share functionality — new feature beyond parity
• Carousel component (T417679)
• Desktop viewer changes