Source: 📖 Django for Professionals ch1 p16
A Docker image is a snapshot in time of what a project contains. It is represented by a Dockerfile which consists of a list of instructions for the image. These instructions can be things like establishing environment variables in the destination container, copying files, and running other shell commands.
A container is a running instance of an image, it is the real thing. The image is like a blueprint, whereas the container is the fully-built building itself.