Why the “none” image appears in Docker and how can we avoid it

Question

When I run the docker-compose build command to rebuild an image in Docker because I had changed something in Dockerfile, sometimes I get \"none\" image tags. Ho

Answer 1

Below are some parts from What are Docker : images?

The Good :

These are intermediate images and can be seen using docker images -a. They don't result into a disk space problem but it is definitely a screen real estate problem. Since all these : images can be quite confusing as what they signify.

The Bad :

These images are the dangling ones, which can cause disk space problems. These : images are being listed as part of docker images and need to be pruned.

(a dangling file system layer in Docker is something that is unused and is not being referenced by any images. Hence we need a mechanism for Docker to clear these dangling images)

So,

• if your case has to do with dangling images, it's ok to remove them with:

   docker rmi $(docker images -f "dangling=true" -q)
  

  There is also the option of docker image prune but the client and daemon API must both be at least v1.25 to use this command.

• if your case has to do with intermediate images, it's ok to keep them, other images are pointing references to them.

Related documentation:

• docker rmi
• docker image rm
• docker image prune