© Minyanville

So this is why people are intensely creeped out by Facebook's facial-recognition database.

In a historical overview of consumer photography from the Kodak Brownie to Instagram, the photo-sharing site 1000memories' company blog estimated that humans have taken 3.5 trillion pictures so far -- and Facebook's servers host 140 billion of them. That's 4% of all photos taken ... ever.

Pretty incredible for a social network that's only been around since 2003. But it makes sense when you consider just how central Facebook is to online life, and the sheer volume of photos people take today.

With smartphone adoption growing like gangbusters since the iPhone's introduction in 2007, it's increasingly the norm to have a decent camera in your pocket at all times. And with flash memory prices at an all-time low (remember when you had to watch to make sure you wouldn't fill up the 128-megabyte card on your dedicated digital camera?), trends like taking photos of all one's meals have become convenient, if cringe-inducing.

Sure, Instagram's growth has been impressive, and new photo-sharing mobile apps launch seemingly every week. But as Facebook continues to dominate social networking -- recent estimates put its membership at 750 million, up 50% from the summer of 2010 -- it's hard to imagine any of the startups as more than a speed bump in Facebook's race to control the world's personal data.

As this infographic from 1000memories shows, compared to its nearest rivals in the photo-hoarding universe -- Flickr, Instagram, and the downright puny Library of Congress -- Facebook is the Borg unicomplex, and resistance is futile:

Photo library
© Minyanville