User blog comment:Harbumz/Introducing Vignette, Wikia's New Thumbnailer/@comment-5007040-20150212181956/@comment-452-20150212182449

I agree. I don't recall ever seeing a thumb rendered like that.

Luckily, some wikis still use the old format, so we can check:
 * http://villains.wikia.com/wiki/Mr._Blonde#Video_Game
 * The thumbnail is: http://img2.wikia.nocookie.net/__cb20140402145704/villains/images/thumb/4/4c/Mr_Blonde_Reservoir_Dogs_Video_Game.jpg/180px-Mr_Blonde_Reservoir_Dogs_Video_Game.jpg

http://img2.wikia.nocookie.net/__cb20140402145704/villains/images/thumb/4/4c/Mr_Blonde_Reservoir_Dogs_Video_Game.jpg/180px-Mr_Blonde_Reservoir_Dogs_Video_Game.jpg.png is supported, but I don't see where that would be used.