First off all in french and i was very bad in english at school so pardon my french, oh no my english...
So here my personnal project on light painting https://github.com/jbreizh/ImagePainting. It's not an original topic, but it's a cool topic, so i try to do it right using all the possibility of the ESP8266.
I try to make a good README.md but it is not up to date for the moment (i change the user web interface by adding the possibilty to convert any picture to bmp). You know what it is : you reach your goal and then a new cool idea appear in your brain and then a new ..... So my doc is a little bit off.
The project work like this : The ESP display bitmap for lightpainting. Those bitmap are store on SPIFFS. The ESP serve a web page to control it (option, action, send and delete picture). Here is a shitty video of an old version : https://www.youtube.com/watch?v=66kzNg7LOFY
Use it, test it, improve it. I am not a coder at all, just a capable user of google . So i think my ESP8266 sketch is pretty ok, but my css; html and js could be improve a lot... and also my english. So don't hesitate to propose your idea.