(I’ve had to do that in particular because of how difficult it is to install some specific PHP extensions on their Alpine image sets

Thanks, seems interesting ...

PHP hardened (distroless) images

That's a good point, maybe I'll change that at some point. The reason, haven't done so yet is that I wanna have the whole supply chain under my control. And know exactly what has been changed since a release.

Why build your own images at all?

Because of different reasons:

• Flexibility: I can modify a container to my needs.
• Trust: I don't wanna rely on something that I don't have under control. An image might contain some breaking changes in the next version, and that could cause me problems when I apply them.
• Learning: By doing everything myself I learn about how to do it.