Creates a stipple picture from the image store in the "image' list. If you'd like to change the picture: Scan your own 45x60 image and import into this project using: https://scratch.mit.edu/projects/66980580/
See here for discussion: https://scratch.mit.edu/discuss/topic/140162/ Colour to grey conversion: http://www.johndcook.com/blog/2009/08/24/algorithms-convert-color-grayscale/
