A Mona Lisa

My paint is smeared upon his wall..
Its a portrait we are 4 feet tall

Can you see it? Look again perhaps, might help if you walk away from your computer a bit, or perhaps view the piece in real life.
Ok its a portrait, or some singer you've probably never heard of, but for the minority that actually know who he is, and then are able to see him in the painting, congratulations! you've earnt your self the title 'Uncle observatron' (note, you do have to be my uncle to earn this title)