Full page illustration presents the general idea of the article. Behavior modification as the main focus of this article tried to be conveyed in the first piece.
Half page illustration talks about a section of the article which questioning the modification theory and believes that it ends up to   totalitarianism.
Spot illustration shows how mobile apps play an important role in our behavior modification, more specifically changing our eating style and keeping the diet.
You can find the article here:
http://www.theatlantic.com/magazine/archive/2012/06/the-perfected-self/308970/