Hidden secret

I was privileged to see again this hidden gem at Oxburgh. The left of the picture is the leather panelled wall of a corridor  on the first floor. There is a hidden door here - you can just make out the lower edge about an inch up from wooden panel below. The hinge is totally hidden.
The panel opens to a very shallow cupboard with a plain plaster back wall - or is it plain? Look carefully and you can see a painted ‘Tudor man’ with his big tunic sleeves, dark hat, and some detail of his face. 
Better viewed from a pace or two back once you’ve seen where he is.
No-one knows how old the picture is, whether it was drawn at the time of the costume, or later of someone dressed up. Unfortunately, due to its position, it cannot be on show to the public as the door opens across the corridor which is narrow anyway. We were having an after-hours training and some of us had not seen it before so the door was opened (then re-locked) ‘extra ‘ is the drawing alone