incidently, part of the reason i chose not to more rigorously support png on sito was that it does not support animated images, so we could not consider it a drop-in replacement for gif on sito (which might be nice). it really kinda bummed me out that png didnt include this, and it wasnt until much later that mng appeared -- which is a sledgehammer of a tool, compared to animated gifs. far fewer browsers support mng (properly) than they do png.
animated gifs are somewhat integral to sito -- witness some peoples id-icons and many squares in hygrid -- even if it isnt part of gridcosm.
however, i will let bygones be bygones and start incorporating the stuff. i love the politics behind png, even with this one tiny bone to pick on its implementation. thanks for using it for the screenshot, and look for support soon!