Extension:Maps was updated in 2020 to re-enable this capability
per this thread in mediawiki-l: https://lists.wikimedia.org/pipermail/mediawiki-l/2019-June/048015.html
User Tigerfell proposes that local images can be used as the basis of a map for this extension. If this understanding is accurate, would someone please provide instructions and/or examples. Thanks!
I just saw your post and I guess you refer to my following statement to the mailing list:
The map extensions you mentioned will display small images with map pieces called "tiles" made by externals in your wiki.
The map extensions fetch images from external servers which in turn render those images based on some input. In case of OpenStreetMap, the input is done by individuals in a Wikipedia-like fashion. It is not possible however, to upload an image via Special:Upload to your wiki and use any map extension to create clickable sections on it. This feature is provided only by Extension:ImageMap AFAIK.