In the result list at https://en.m.wikipedia.org/wiki/Special:Nearby (with location permission enabled), articles without images lack the "no image" icon, with the following error message showing in the JavaScript consult (in Chromium under Linux):
Failed to load resource: the server responded with a status of 404 (Not Found) https://en.wikipedia.org/static/1.26wmf5/extensions/MobileFrontend/resources/mobile.pagelist.styles/images/noimage.svg