Welcome to day 4 of our series on containerd internals! Container images are the mechanism that we use to capture a container’s filesystem, distribute it to nodes that will eventually run containers, and ensure that containers start from a known-identical configuration. In many ways, images are the defining characteristic of a containerized system; they are the interaction point for users who want to create a workload and make it repeatable and predictable. Without images, you could still have similar isolation characteristics that are available in containerized systems today, but it would be more difficult to achieve reliable, production-ready, and understandable workloads.