Dropbox also has recently added an auto-upload feature for photos from mobile devices, which also increases file usage.

FORBES: Dropbox Doubles Space For Pro Accounts

Anyone who's returned from an event with a virtual armful of photos may have been frustrated with Facebook's upload interface, which until now has involved a less-than-intuitive file browser.

ENGADGET: Facebook adds drag-and-drop photos, trials simplified Timeline and delivers new privacy controls