No, because you could have it that the device is always identifiable, but nevertheless producing a randomly varying sequence of images. Take printers for examp

No, because you could have it that the device is always identifiable, but nevertheless producing a randomly varying sequence of images. Take printers for example, with some known to print a signature. Clearly they can still print a sheet a solid colour (or a number 0-100, or something character or whatever) at random (given some random source & control for doing so I mean) despite the device being identifiable.