Image map in the lead section (no other images on the page): http://reading-web-staging.wmflabs.org/wiki/PageImages6
The API doesn't return the image map, but it should: http://reading-web-staging.wmflabs.org/w/api.php?action=query&prop=pageimages&titles=PageImages6&pithumbsize=100&pilicense=any
For other test cases see T87336#2858587.
Should it?
If an image map is used in an article is it not used to make certain areas clickable? Would that translate well to a page image?
Do we have any real world examples where an image map may be more suitable than the current choice?
Was this decision intentional and documented anywhere?
Looks like we need to analyze articles from https://en.wikipedia.org/wiki/Category:Articles_containing_image_maps.
However, if an image map is the only image on a page, we may need to consider returning it.
That sounds like a good first step. My concern is we shouldn't introduce code if it's not useful due to the time it takes to implement this kind of change and the added maintenance cost of coupling ourselves to the ImageMap extension.
I believe this is the correct behaviour. Until we see some examples in real world wikis we should decline this.