Surpassing the flock of its rival web photo-sites, Facebook Photos just lately uploaded its 10,000,000,000th photo! And since Facebook keeps four different-sized copies of each of the uploaded photos, the site has 40 billion files just for the photos!

Having touched the ten-billion mark in terms of uploaded photos, Facebook Photos has become the biggest photo site on the web. As per comScore data, 69 percent of the monthly Facebook visitors visit Photos site. Other estimates reveal that the site serves more than 15 billion photo images per day, with the photo traffic maxing out at more than 300,000 images served per second.

Figuratively speaking, Facebook has clearly pulled ahead of two of its closest competitors - Photobucket and Flickr - as per September 2008 analysis, when Facebook Photos had 23.9 million unique visitors, and Photobucket and Flickr had 21.3 million and 19.5 million unique visitors respectively.

By January, the figures of monthly US visitors to photo sites underwent a dramatic change, when the number of Facebook Photos visitors shot up a whopping 41 percent to reach 33.6 million; as against a mere 7 percent increase - to 22.8 million - in visitors to Photobucket. 

While the gap between Facebook and its closest US rival Photobucket increased 10.8 million; Facebook's gap between its closest global rival Flickr increased from 41.2 million to 87 million unique monthly visitors!

With inputs from Techcrunch and comScore reports.