> > I don't know about Exif data but icc profiles can be > embedded in them now, the format is open and is being > improved. Maybe in time.
Not really. The PNG format is in the last stages of being accepted as an international standard, and is therefore not being changed. Addition of EXIF data would come, if at all, in a future version. There is some level of extensibility built into PNG; it's possible to register new chunk types, and textually-encoded data can already be associated with an image. But even if these mechanisms prove sufficient (which is possible), until an encoding of EXIF data is commonly accepted you can't really say EXIF is supported by PNG.
