When you finish painting an image you are taken to the Share screen, where you can watch a Time-lapse animation!
The animation consists of a short video that groups the main frames of the painting process and displays them at an accelerated rate. In other words, you can watch your progress while working in a picture!
Just turn-on the Time-lapse button when you get to the Share screen to watch your painting! You can also share the Time-lapse with your friends!