occurs for example on: https://wiki.gentoo.org/wiki/Project:Artwork/Artwork screenshot attached. Reproducible: Always
Created attachment 656218 [details] screenshot.png
It took a bit of leg work to determine the cause of this issue. The web server hosting the wiki has a rate limiter for 'get' resource requests. Any connection that requests more resources than the limit will get 503 Service Temporarily Unavailable errors. This is by design due to how many requests hit the wiki every day. The work around for this issue is to manually refresh the page (key press F5 in most web browsers) a few times so that the web browser will cache the thumbnail resources. With the amount of PNG images on the page presently (about ~20) 4 or 5 refreshes should cache all the images. This issue will occur on ANY wiki page that exceeds the request threshold set in the rate limiter, not just the Artwork showcase page. Unfortunately, unless infra wants to build out an HTTP Cache (such as Varnish or something) on the front end, this annoyance will not be going away.
I tweaked some other settings in the meantime; so users should get the page loaded fully.
Thanks for all your help, Robin!!
