See
https://bugzilla.wikimedia.org/attachment.cgi?id=10931
(from bug 39028)
Failed to load resource: the server responded with a status of 404 (Not Found)
https://en.wikipedia.org/wiki/Extensions/WikiEditor/modules/images/toolbar/example-image.png
Version: master
Severity: normal
URL: https://en.wikipedia.org/wiki/WP:Sandbox?action=edit&uselang=qqx
Interesting, this seems related to shorturl.
The issue is reproducable on multiple titles, but if you use the index.php version, everything is working.
https://en.wikipedia.org/w/index.php?title=Wikipedia:Sandbox&action=edit&uselang=qqx
Fixed in https://gerrit.wikimedia.org/r/17644
There is more stuff wrong there. Note that the magnify is not floating to the right atm. This is because the 'template' in the message is not wrapped in a .thumb div.
I'm not really sure why we are using a template at all actually. Now if we change the thumb layout (not unthinkable, see https://gerrit.wikimedia.org/r/#/c/9967/ ) we will need to adapt all the i18n messages.