Many political cartoons have a little guy on the bottom corner making snarky comments.    Chris Tombrello and Chad Lupkes suggested that Pat Oliphant may have invented this form [snarky comment guy]. His little penguin was named Punk. Chris thought the insets might be called “cartouches”, but the term doesn’t quite fit. (See http://oldprintgallery.wordpress.com/tag/cartouche/ and http://en.wikipedia.org/wiki/Cartouche_%28disambiguation%29 .)

I propose calling the little cartoon commenters “snarkies.”

I added a snarky to the bottom left of my image about Bill Gates, in response to Elizabeth Hanson’s observation that Gates’ donations to education often supported a corporate takeover of public education.
Hey, Bill Gates! You've given money to fight diseases, fund education, and stop gun violence. How about donating to fix our unfair tax system that favors  people like you?