Quite simple. I added an option to set your pen size. Added writing at the start saying: "Choose a backdrop:". Made the code tidier. I did that by right clicking in the editor and pressing 'Clean up.') You no longer need to click the mouse to start drawing. When you pick a pen size, it automatically 'clips' onto the mouse-pointer.
All credit to @Gumdrop229 for the original. :)
