Facebook has just announced that it has bought the Instagram photo-sharing service for a cool $1 billion (around £630 million).

The shock acquisition comes just days after the filter-friendly application launched an Android app to sit alongside the iOS service, which has over 30 million users.

The social networking giant will pay Instagram $1 billion in cash and stock from its upcoming IPO. The full team, including CEO Kevin Systrom will stay on.

CEO Mark Zuckerberg announced the deal on his Facebook page, saying hook-up will help to create the best possible experience for sharing mobile photos.

Committed to growing Instagram

Zuckerberg also said that Instagram will remain as a standalone service that Facebook is committed to developing as independent entity.

He wrote: "I'm excited to share the news that we've agreed to acquire Instagram and that their talented team will be joining Facebook.

"For years, we've focused on building the best experience for sharing photos with your friends and family. Now, we'll be able to work even more closely with the Instagram team to also offer the best experiences for sharing beautiful mobile photos with people based on your interests.

"We believe these are different experiences that complement each other. But in order to do this well, we need to be mindful about keeping and building on Instagram's strengths and features rather than just trying to integrate everything into Facebook.

"That's why we're committed to building and growing Instagram independently. Millions of people around the world love the Instagram app and the brand associated with it, and our goal is to help spread this app and brand to even more people."

Systrom psyched

In a post on the Instagram blog, Systrom moved to assure users that the app will remain separate with all of the features members love, while the team will continue to develop new features.

He said: "It's important to be clear that Instagram is not going away. We'll be working with Facebook to evolve Instagram and build the network. We'll continue to add new features to the product and find new ways to create a better mobile photos experience.

"The Instagram app will still be the same one you know and love. You'll still have all the same people you follow and that follow you. You'll still be able to share to other social networks. And you'll still have all the other features that make the app so fun and unique.

"We're psyched to be joining Facebook and are excited to build a better Instagram for everyone."

Huge growth

Instagram has become comfortably the most fashionable, and often the most simple way to edit and upload photos over the course of the last year or so.

With a range of simple effects and filters giving photos a decidedly retro feel, snaps can be shared in just one click.

The app, which grew from one million users in January 2011 to 15 million by the end of the year, and doubled again to 30m at the time of writing, was named App of the Year by Apple for 2011.

The newly-minted Android app obtained one million downloads in the first week.