SuperHamster on most wikis.
Kevin Payravi on the Wikimedia Commons.
KevinPayravi on Toolsforge.
Experienced this on Chrome for Windows at San Holo on en.wiki. Like Kaldari, directly hitting the thumbnail's URL prompted the browser to download the image. After going to the filepage on Wikipedia and purging the cache, thumbnail started working normally again.
Replacing with gov building icon
GitHub repo created: https://github.com/KevinPayravi/Cite-Unseen
@Aklapper Ahh, gotcha, will do - thank you!