Are there any open source sprite format?

PNG just plainly sucks. I has no support for animations, timing or delta compression and sequence names. Also, PNG is slow at random access (you have to decompress image before use). Proprietary formats (like Diablo 2 DCC) are much better, but highly specialized for their games: some have no true color, other have no directions.

>>32
Because it allows color cycling and recoloring? Because it original was drawn as 8-bit? Because 8-bit pixelart looks better than blurred 24-bit continuous tones?