Just like human vision, computer vision has its limits. For example, if there are objects on the photo never before seen by the neural network - e.g. an anteater, extraterrestrial life’s statue or a medieval stained glass window - it may not separate them from the walls correctly. In some photos, even a human cannot be sure if they see an actual cat in a room or a painting of a cat on the floor. By the same token, by merely looking at a picture, you may not always be able to say how big a painting on the wall is, or distinguish a brick wall from a brick wallpaper on said wall. Computer vision may experience the same difficulties.