What role, if any, should `poster` play?

[zachernuk]

I'm personally concerned that poster is under-specified for the things that an author will want to do to represent a <model>. First, the syntax doesn't allow for alternative file formats, for different resolutions or aspect ratios or prefers-color-scheme etc. Add to that the possibility that a good poster/placeholder for a model element may even be another model, and it makes me wonder whether there's an appropriate way to meet these needs at all. What does everyone else think?

/agenda