>>9
APNG (which I'm assuming you're referring to when you say ``PNG does animation''; in reality, the ``PNG that does animation'' is MNG) is supported practically nowhere as well, and certainly isn't anything approaching a standard, unlike MNG. It's a dirty hack, the only advantage of which is that it can pretend to be a regular PNG to software that doesn't support it, and that isn't the behavior you want 99% of the time.