Here are some images that show the process of taking a very quick small sketch in a notebook, scanning it in and turning it into a presentable coloured image for a PowerPoint presentation.  The sketch was small and smudged, but had a lively charm that would have been lost if the image was redrawn more carefully.

this next image shows the layers used to colour the illustration, but with the lines removed:

And finally the finished illustration, on a grey background selected to fit into the presentation: