Debugging a slow photo library

I ran into this again last week, so here is a short note for future me. Naming things clearly helped more than any clever trick. There is probably a better way, but this one is easy to remember.

I wish someone had told me this when I started. Most of the time the simplest tool is good enough. Measuring before changing anything saved me from a pointless rewrite.

It is worth writing down the commands you only need twice a year. I keep relearning this, which is exactly why it goes here. Plain text keeps winning for small personal projects. After cleaning things up, the whole thing runs noticeably faster.