> A Debian Slim Docker image is 20MiB, and in my experience by the time you install all the dependencies of your app in an Alpine image, it’s bigger than the equivalent based on Debian Slim.

This is true, also while Alpine is an excellent base image, some people have run into troubles with musl/busybox and prefer to use Debian/Ubuntu or whatever else they're familiar with as their container base.

Then again, I kind of went in the opposite direction and use Ubuntu as the base for all of my container images and install software "the normal way": for example, getting OpenJDK through apt as I would on a server with Ansible, or for my local dev machine, without any of the fanciful optimizations or clever hacks to keep the file sizes down.

The downside of this is that my base images are multiple hundreds of MB in size (even after cleaning apt cache in the same step as doing the install, to avoid adding that to the layers), but on the bright side that hardly matters because I use the same base images for all of my containers so only the changes for that particular image need to be transferred through the network and like 40-80% of the layers remain consistent: https://blog.kronis.dev/articles/using-ubuntu-as-the-base-fo...

It's not "optimal" from a size perspective, but it's delightfully simple and approachable.