Nice; it's that background effect at work again, but stronger. I think I've figured out that she's sitting hard up against a large window?
Since the background effect is stronger in the close-up, I am thinking it isn't grain at all, but the glass doing its thing. If it was not a close-up but just an enlargement from a similar sized image as the first, then yes, it could be a film grain effect enlarged due to, well, enlargement of the image.
Like I said, makes you think.