If page
http://hr.wikiquote.org/wiki/MediaWiki:Previewnote
contains image, it is wrongly parsed somewhere and instead of image, output is rendered as broken HTML.
When you save image it is rendered right (on MediaWiki:Previewnote page), but when this message is shown above preview of every page any user edits, it's broken.
1.20wmf10
Version: 1.20.x
Severity: critical