The official Python image for Docker is quite popular, and in fact I recommend one of its variations as a base image. But many people don’t quite understand what it does, which can lead to confusion and brokenness. In this post I will therefore go over how it’s constructed, why it’s useful, how to use it correctly, as well as its limitations. In particular, I’ll be reading through the python:3.8-slim-buster variant, as of August 19, 2020, and explaining it as I go along.