It's only been a few days since Facebook shelled out $1 billion in cash and stock to purchase Instagram, but now we've got some information on how the deal came together. According to The New York Times' anonymous "people with knowledge of the matter," CEO Mark Zuckerberg was at the forefront of the entire acquisition, unlike previous (and smaller) transactions. Apparently it all came together over a matter of two days — Zuckerberg called Instagram CEO Kevin Systrom last Friday and said he wanted to buy the photo sharing service, and by Sunday all of the details were worked out. Zuckerberg's phone call was just days removed from the release of Instagram for Android (which was downloaded over a million times in a day) and a $50 million funding round that brought the company's valuation to a total of $500 million. Ultimately, it took Facebook $1 billion to claim the photo sharing service — and its 13 employees — as its own.