A Docker image contains the code used to create a Docker container, such as creating a Nginx web server, or a mySQL server, or a home grown app, and the list goes on. In this way, an image is like a template used to create a container. An image is kind of like a virtual machine, but much more light weight, using significantly less storage a memory (containers are usually megabytes in size).
The docker start command is used to start a container. In this example, the container named my-container will be started.
docker start my-container
docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d937372c09ab9 b939aa938add9913 "/docker-entrypoin..." 6 minutes ago Created my-container
The -a or --attach option can be used to print stdout and stderr to the console.
docker start --attach my-container