Come For A Drink is my first game (ever) and also my first time using Ren'Py, a visual novel engine. I was pleasantly impressed with all the features available (especially the tutorial game packaged with the engine), however, I struggled with the official documentation, because I'm a python/game making newbie, overall it wasn't visual enough for me (a visual learner), and I also struggled to understand, architecturally, how all the rpy files worked together (or separately) when packaged.
Here's a quick visual tutorial on making a gallery in Ren'Py 7.0. Galleries are a nice way to track your progress in game (if you have multiple endings) and/or show off that fancy CG you made that would otherwise only be seen for a split second during game play.
Please note that I'm NOT an expert, I don't understand all this code, but this is working code that is in my game! It is the result of a lot of uninformed trial and error.