Thanks you, this article clarified a lot of things for me. What are your thoughts on image squashing?

Good and valid points about the shared base image use and how it can reduce the storage and transfer time/costs. These aspects are usually not discussed because the math becomes a bit more complicated and environment specific :-) However, some of the assumptions in the post are not always true or, at least, not to the same degree. For example, the size of the 'frequently changing layers' is not always ideal because not everybody is a Dockerfile ninja. Not all environments use the same base image too. Companies usually end up with a set of different base images for many different reasons (different language stacks, different framework versions, different base image preferences, external dependencies, etc). Few environments have only one base image. 3rd party Docker images also make things more fun :-)

DockerSlim tries to give you smaller images 'for free' where you don't have to worry about being a Dockerfile ninja and you don't have to use a small Linux distro that may break your application.