The LABEL command can be used to add extra information to the image. This information can be anything from a version number to a description. It's also recommended that you limit the number of labels you use. A good label structure will help others who have to use our image later on. However, using too many labels can cause the image to become inefficient as well--I would recommend using the label schema detailed at http://label-schema.org/. You can view the containers' labels with the docker inspect command:

$ docker image inspect <IMAGE_ID>

Alternatively, you can use the following to filter just the labels:

$ docker image inspect -f {{.Config.Labels}} <IMAGE_ID>

For our example, we add two labels: one to identify who maintains the Dockerfile by adding maintainer="Russ McKendrick <[email protected]>" and another, a description, description="This example Dockerfile installs NGINX.".

Generally though, it is better to define your labels when you create a container from your image rather than at build time, so it is best to keep labels down to just metadata about the image and nothing else.