MediaViewer makes a dictionary of <img> elements on page load (see the constructor and processThumbs() in mmv.bootstrap.js) and cannot handle content added dynamically. (The page parsing logic is crappy anyway and in need of a rewrite - e.g. T77220)

In T101951#1381077, @Tgr wrote:

MediaViewer makes a dictionary of <img> elements on page load (see the constructor and processThumbs() in mmv.bootstrap.js) and cannot handle content added dynamically. (The page parsing logic is crappy anyway and in need of a rewrite - e.g. T77220)

Is this considered a bug in MediaViewer then?

More like tech debt.

How would an application normally react to a VE save? Is there a hook, or an event to listen for?

I don't think there is a VE-specific hook... We do fire wikipage.content. I think @Mooeypoo has had a similar problem before?