Debian Slim is a variant of Debian that’s optimized for running in containers. It removes a ton of libraries and tools that’s normally included with Debian.

I know Alpine is also an option but in my opinion it’s not worth it. Yes, you’ll end up with a bit smaller image in the end but it comes at the cost of using musl instead of glibc. That’s too much of a side topic for this post but I’ve been burned in the past a few times when trying to switch to Alpine – such as having network instability and run-time performance when connecting to Postgres. I’m very happy sticking with Debian.

Because the official images are intended to be learning tools for those new to Docker as well as the base images for advanced users to build their production releases, we review each proposed Dockerfile to ensure that it meets a minimum standard for quality and maintainability. While some of that standard is hard to define (due to subjectivity), as much as possible is defined here, while also adhering to the "Best Practices" where appropriate.

Snaps each pick a ‘base’, for example, Ubuntu18 (corresponding to the set of minimal debs in Ubuntu 18.04 LTS). Nevertheless, the choice of base does not impact on your ability to use a snap on any of the supported Linux distributions or versions — it’s a choice of the publisher and should be invisible to you as a user or developer.