Thank you both, John & Geert, for your comments. In general, https://wiki.debian.org/Docker warns that, for the images at https://hub.docker.com/_/debian, "you may not trust their maintainer on having done the right thing for you." That sounds awfully like a security warning. Yet Tianon and Paul Tagliamonte maintain those repos, so they should be perfectly safe and reliable, no?
If so, I'll tone down the language to say that the images are general purpose, and the reader may want to customise their own. If I understand Geert's advice, the official Docker images use debuerreotype, so your link to the GitHub repo would, in theory, allow me to roll my own containers virtually identical to the official images. As not to duplicate effort, I may just link the wiki/Docker page to GitHub. Tying in John's commentary, it appears mkimage.sh got moved out of docker.io. In fairness, I had no way of knowing that mkimage.sh referred to the mkimage package and not some custom script in docker.io. Based on the official images, debuerreotype would be the "recommended way" to build an image over mkimage.sh, right? I just want to make sure my foundations are correct before I start breaking things.
