I'm surprised you did not include a picture of a bicycle with a bicycle engine kit installed. They're very popular in China for very long commutes. Grubee and others imported 7,000,000 of the Chinese bicycle engine kits into the USA before the EPA banned them from importation Jan 1 2006. They're so popular here there still being imported and sold illegally in the USA across the open border on weekends with Canada by the tractor-trailer load. Below is the link on how to install one of these engines on a bicycle.
http://www.simpsonmotorbikes.com/48c...structions.htm

I did find a picture of an electric bicycle. It's the photo with the file name of bike-sleeves-visor.jpg. If you look closely at the rear wheel you notice it has a very large hub. That is the electric motor!

The image below is a Flying Pigeon with an engine kit installed.