Difference between photo and picture
To most people, the words photo and picture are interchangeable. But are they really? Let’s examine the two words and give a clearer definition of them.
Photo
A photo, or a photograph, can only be used when it has been produced by using a camera. It is a very restricted term, so you have to be careful when you want to use it.
Picture
The word picture has a less restricted use on it, which is in fact a very common term with multiple meanings. We can use this one for a lot of things like a drawing, a painting, a cinema film, a portrait or, a photograph too.
If one refers to a photograph as a picture, the object itself is probably a combination of a photo with text or graphics rendered on it. Picture can be employed in special cases like something produced in your mind; an impression one has of somebody or something described to them; or from your memory.
Another related word is image. This word is a more generalised one. An image can be a visible impression obtained by any device such as a computer, telescope, camera, video screen et cetera. It can also refer to a representation of an external form of a person or thing among other meanings.