Facebook has a larger photo collection than any other site on the web. According to an extrapolation of photo upload data reported by Facebook, the site now houses about 60 billion photos compared to Photobucket’s 8 billion, Picasa’s 7 billion and Flickr’s 5 billion.Photo organizing Facebook app Pixable has used data from a sample of 100,000 of its users to give some insight into the contents of Facebook’s huge photo collection. According to the data, weekends are the most popular days for uploading photos. Middle-aged users and those in their twenties upload comparable numbers of photos, but the older group uses significantly fewer tags. Women upload about twice as many photos as men — which might be good for everybody, as recent research suggests photos with women in them are generally preferred. “Guys prefer photos with girls. Girls prefer photos with girls. Pretty much everyone prefers photos with girls,” explained Pixable CEO Inaki Berenguer at a recent Social Media Week panel.( source : Mashable.com