Go rent Toy Story, a megabudget picture which attempts to render real people. Then, either 'fess up to your ignorance or make an appointment with a qualified optometrist.
I'm not a computer scientist, so I can't dispute that directly. I can tell you, though, that there are lots of computer consulting companies out there which charge lawyers a lot of money for telling whether an image is genuine or has been altered by, or generated on, a computer. If they've been scamming my law firm (and the courts in which they testify as expert witnesses), I'd love to know about it.
I've worked in photography and digital imaging for years. Even using the best technology available today, one would have a difficult time creating an image of a virtual child that would pass the forensic scrutiny of digital imaging experts. To create images that even come close on a scale of hundreds or thousands of images would be so time consuming as to make this a purely hypothetical argument! That's a fact.
the police must prove that it is an actual child. The perp does not have to prove he has the skill to create a digital image.
Surely you realize yourself what a ridiculous statement this is. Of course a defendant doesn't have to prove he has the skill to create a digital image. But if he's on trial, it would certainly be in his best interest to demonstrate that. Were you just not thinking in your haste to make a response?