"You know, of course, that the portraits at Hogwarts serve the current Headmaster, whoever that may be.  We may choose to aid past headmasters as well, provided they are not dead.  I was something of Severus’s eyes and ears when he was Headmaster at Hogwarts last year, and you might say I have kept an... eye on things.  However, spending most of the year tucked away in your bag, there was little information I could give him."