Digital pictures, particularly with all the various enhancements they go through today...they aren't in the same class as film pictures of old, and can be said to be "not real".
Heh. Ever developed film? Not trying to be snarky, just remembering some stuff I heard decades ago. This isn't exactly a fresh topic.
Which is not to say there isn't a gradient of "fake"; obviously some are more manipulated ( or fabricated ) than others. Doesn't change the underlying point, however.
To me the threshold is fairly distinct and easy to see: Is the work being done on the pixels, or is it being done on the image? Are you looking at a curve of values and applying a transformation, or are you looking at a 2-dimensional set of pixels and re-positioning or re-constructing them?
Or.. in film terms- Are you playing with the intensities of light (or the balance of chemicals...) as you go through the developing process, or are you going over a photo with an airbrush and using your brain to put details back in?
There's a huge difference between an AI looking through a stack of exposures to blend in the most detailed one and pulling a stock photo of the moon and grafting it into the image. Splitting hairs does not change this even if the process does get crazy complicated an nuanced.