Move Me -- Martyn Wilkinson <mgw@picdar.co.uk> writes in regards to the graphic file formats article in NetBITS-007:
There's one point Glenn forgot to mention: GIF files support multiple "frames," which means they can be used for simple animation. I believe this feature is exclusive to GIF since, until Netscape supported it, no one had bothered with this rather obscure part of the GIF specification. PNG was designed before Netscape supported multi-frame GIFs, and the designers didn't see the point of supporting this completely unused feature. Pity.