Facebook, the world's largest social media network has just announced it will pay a whopping one billion dollars to buy the photo-sharing app Instagram, which lets users add various filters to their photos before sharing them online. The company was only set up 18 months ago and despite having almost 30 million users, it still only has 13 employees.

The Founder of Instagram, Kevin Systrom is set to land a pay day of four hundred million dollars for his 40 percent share of the business.

Facebook CEO Mark Zuckerberg announced the deal on his own Facebook page, saying "This is an important milestone for Facebook because it's the first time we've ever acquired a product and company with so many users."

This announcement comes as Facebook prepares to float on the stock exchange later this year which could value the company at up to one hundred billion dollars.