Somewhere I read that a difference between a painted and a photographed portrait is time.
While a photographed portrait is created in an instant, the click of the camera, a painted portrait takes a lot longer.
If the model poses for the portrait, his or hers expression changes slightly during the creative process thus influencing the final result.

These portraits are in the middle of the two:
They are photographs but taken with a specially constructed camera that takes
about 56 pictures of the model. Each picture is part of the models face.
It's like a panorama photo of someone's face.
The complete process takes about 5 minutes to complete, and requires the model to sit still during that time. As this is not completely possible, during the process, facial expression may change a little, just like in a painting ...