Betty Boop was originally created by Max Felischer, the eldest of the three Fleischer brothers (Max, Dave and Lou), who founded Fleischer Studios together. In it’s prime time, from the 30s-40s, Fleischer Studios was the most significant competitor to Walt Disney Productions. Max in particular is the credited animator of characters such as Koko the Clown, Popeye the Sailor Man, Superman (the 40s cartoon), and Betty Boop.
This image is a sketch from a large collection of Fleischer material, that recently came into the hands of an animation art-dealer named Mike Van Eaten. One can see the careful calculation it took Max to make Betty perfect.
Read more about this and see more of the Fleischer Drawing collection here: http://www.cartoonbrew.com/classic/fleischer-studios-gold-76202.html, in an article on “Cartoon Brew”– seriously an awesome site if you haven’t been there yet!