>were not experienced coders.

I think they may have exaggerated that. It another article Krieger say "in high school, one of the things I loved doing was this after-school program where you would teach computer skills to some of the maintenance folks at school." Which he taught, so presumably he was coding at school. Then "studied human-computer interaction" at Stanford. Then he was a "user experience designer and engineer at Meebo." Then Instagram. So probably some years of coding experience if partly on a hobby basis.

http://www.theverge.com/2013/5/13/4296760/sketching-instagra...