A photo is the actual picture of someone as taken by a camera. A picture can be either a drawing, painting or a photo. It can also be a mental picture. This means that a photo is always a picture, but a picture is not necessarily a photo. An image can be any likeness of a person or thing. It can be a painting, picture, photo or even a sculpture. An image can also be used to refer to a reflection or the picture of something transmitted through the eye. This means that a photo is always a picture and a picture is always an image. However, an image is not necessarily either a picture or photo.