A few months ago I ordered a wildly cheap Bluetooth thermal printer from AliExpress and got it to print on the iOS app, but I wasn't satisfied with the designs and options on the app and have wanted to create my own prints ever since.
I've been poking at NaitLee/Cat-Printer for the past week to try to get it to generate images with Pillow instead of having to rely on the web app and I finally got it working!