Alpine Linux-based Docker images are small, but they can still bloat up quickly. If you're concerned about image size, search for alternatives, like Minideb.

When the Docker revolution started, one argument among many in favor of using containers instead of virtual machines was their size. Container images were supposed to be small.

However, several anti-patterns quickly emerged in the early days of Docker. First, most people wanted to treat containers just like VMs, hence they wanted an SSH server in them, they wanted to run multiple processes in them and they wanted their regular Linux distributions.

This quickly ballooned the size of Docker images that could be pulled from the Docker Hub. Official Ubuntu and CentOS images used to be above 600 MB. Once dependencies and application code got added, it was not rare to see several GB Docker images around.

Well organized information about volumes in Docker.