Proper centering / image location pinning in anonymity-is.tex
I spoke to @ahf about this at 37c3, and he suggested I open a ticket.
You can see the "unveiling" in action on slides 11-14 of https://freehaven.net/~arma/slides-37c3.pdf.
And the goal is to pin the locations from slide 14, so the various pictures show up in the right locations on the earlier slides.
(Once the latest merge requests have been merged, you will be able to see the source file properly in arma-37c3-2023/anonymity-is.tex.)