In the dialogue Delbert Grady says, “I'm sorry to differ with you, sir, but you are the caretaker. You have always been the caretaker, I should know, sir. [I've always been here.] ” If he’s "always been" there he must be in the final photo? If he's real and not a product of Jack’s imagination and what he says is true, he must also be there with him in the final photo and he must look exactly the same. But the fact is that he isn't there and they were both "caretakers" and Grady succeded in "correcting" his family where Jack didn't.
Stanley Kubrick's dialogue is precise and it's clear that Delbert Grady is a lier – it’s so simple and so obvious.