Thread:Daifukkatsu/@comment-24398933-20140626204718/@comment-6003396-20140630042729

I'm somewhat sure that the browser does not download the full resolution image and then scales it down, but rather wikia creates scaled down versions of uploaded images which are then downloaded and displayed by the browser (like this). I'm not 100% sure on this, but if it is correct, then pngs are preferable.