This is a good idea, and is something I did when I was learning (specifically: made a 'ship' with bounding box area, then loaded in 'ship parts' from a .bmp for each tile which was changeable by click... then brought up a custom paint program with a gb gradient and r slider to paint over the ship parts. This way I got image loading, bounding box selection and modes, variable size collision boxes for expanding ship size by using more tiles, and individual pixel manip for painting into an overlayer)