It's an interesting app, somewhat similar to Dynamic Auto Painter in that it lets you see the brushstrokes being laid on canvas one by one and the painting being formed in front of your eyes. While it really is possible to export the image at any stage of the painting process, you MUST wait till it's 100% completed (which may take up to 5 minutes), without leaving the app, otherwise it will just crash upon your return and all you are going to see is a black unresponsive screen. The only solution to that is deleting the app and reinstalling it.
Also, while the image is being painted, the large beautiful artsy brushstrokes are being laid randomly all over the canvas and they exceed the image boundaries and it looks really fantastic. However when you export the painting, it does not let you export the entire painting that you see, those beautiful brush strokes are cropped off and you just get what's inside the original image boundaries - which is logical, but it would be great to have an option to export the entire canvas including those big brushstrokes.