The concept behind the picture is amazing and wonderfully dark. The expressions, the black clothes and thinness of Harry, the writing- oh, my, the writing! I love the different languages you used, the references from the book, even the touch of Hebrew which makes it rather interesting. :)
The papers on the wall, on the floor- wow, Harry needs some serious help there, and Snape doesn't look thrilled about it himself. Ahem.