Poster Image Displayed Before Interaction

[tomcrane]

Poster image displayed before interaction

(Provide link to index.md of the issue, if available. To be filled in after issue is created - you need the issue number!)

Use case

I wish to provide the user with something to look at before they choose to start interacting with the object, and/or while they wait for it to load/buffer.

[tomcrane]

Discussed in WG meeting - this is the same modelling as for journals or newspapers, but it's worth producing a separate recipe for a journal splash / poster image. It will make it easier for people to find, and copy.

[triplingual]

Note to self: working example (more or less) of this idea in v2 at http://universalviewer.io/examples/?manifest=http://wellcomelibrary.org/iiif/b17307922/manifest#?c=&m=&s=&cv=&manifest=http%3A%2F%2Fwellcomelibrary.org%2Fiiif%2Fb17307922%2Fmanifest and https://uv.netlify.app/#?c=&m=&s=&cv=&manifest=http%3A%2F%2Fwellcomelibrary.org%2Fiiif%2Fb17307922%2Fmanifest (note the difference in placeholder image sizes). Behavior is a little more like accompanyingCanvas, but.