Unwelcome Buyer

This picture was taken with a digital camera. My friend took this picture while house shopping last year. The picture he took of the house before entering shows nothing strange. He is sure he took pictures inside the house since he wanted to share pictures of all the houses he viewed. But there were no photos of the inside of this house on the camera. When he left the house he took this photo. None of the other pictures he took had anything on them.