Image: Image is the picture which are saved in electronic form in our phone’s gallery. For instance, any picture file in your computer.
A saved drawing by using Microsoft Paint software is an image but not a photo.
Image also means a kind of behavior or impression a person presents to the public.
Image 通常指的是电子图片。比如存储在我们计算机、数码相机、智能手机里的照片、图片。Image 也用于描述一个人展示给他人的行为举止或印象。
Photo: Photo is a short form of photography. It is from the word Photo (light) + graph (instrument for recording). Basically, photos are those pictures which are captured via camera.
If a camera shoot is printed, it is a photo not an image.
Photo 单词是 photography 的简写。是由两个单词 photo(代表光线) 与 graph(记录设备) 组合而成。因此，photo 特指用相机拍照这种方式获取的图像。通常特指相机拍摄后洗出来的照片。
Picture: Pictures are the paintings or drawings of anything created by humans, which is a broad and generic word used to define any visual representation of anything.
When someone says “draw me a picture” they might want you use pencil and paper to create a portrait(肖像) for them.
A paper drawing is a picture but not a photo or an image.
Picture 是指各式各样的人类创造出来的绘画，适用范围广。强调的是人类通过自己的劳动 (比如使用铅笔在纸上作画) 创造出来的，而不是利用科技制造出来的“画”。