Copyright Scare

As I'm working with memes lately I came across some copyright concern. When does a meme qualify as fair and common use after becoming a internet sensation and widely circulated, and when can the originating image that inspired the meme sue for license infringement. Turns out Getty Images got on board the Troll train and started firing off license infringement claims to suck up some extra money from the internet.
The meme in question is the Socially Awkward Penguin that supposedly is a National Geography image that Getty owns the rights to license, or at least the right to bully web sites, by the sounds of some of the articles. Well being a semi creative I wanted to take a page out of GetDigital book and create a legally safe inspired original illustration of a penguin on a blue meme background.
And because I believe memes belong to the internet, I'm sharing this illustration freely.