The pictures are in docs/guides/images/<user>/. They are made by the end-to-end tests with test data. A
normal run (python manage.py test e2e) leaves them alone. When the guides change, update them with
python manage.py test e2e --update-guide-images and commit them (see e2e/__init__.py).
These guides are also the app's Help pages: after a guide changes, run
python manage.py sync_help_pages (on Heroku: after the deploy).