Hi Zens!
Thats only a info to all zenPhoto coders and users:
I have coded a OpenStreetMap view for single image webpage with only one pointer and for a full size single album webpage with pointers and clusters for all published images in OpenLayers 5.3.0. (OL 6.0.x - 6.1.1 [latest version today] don't work with IE and older Android).
Sadly i don't have time and know to code a plugin with this. So far it's only a mod, for my ZenPhoto webpage.

Some time ago I had coded a all images map in Leaflet. I can not recommend that anymore. It is not well coded. It's not lightweight.
https://github.com/mebels/zenphoto-osm-fotomap

My new version with Openlayers is lightweigth. Specially for mobil devices, with button load on single image pages. And, the all images map works fine on mobile devices with over 20.000 photos. Without Ajax. Pure JavaScript.
If someone is interested, please wrote it here! I'll occasionally drop by here. Coders for coding a plugin are welcome.