Yes; this PNG is not a complete xkcd comic. Whoever submitted this (I'm looking at you, anirbas :-) will now have to reread every xkcd comic to get the alt text, too. For those who don't know what I'm talking about, mouse over any xkcd cartoon and leave it there for a few seconds. (Firefox users: install https://addons.mozilla.org/en-US/firefox/addon/1715 first.) For those didn't know: I feel your pain. That was me about six months ago.