The meteoric rise of Snapchat reached a milestone last week when its creators turned down a reported €2.2 billion offer from Facebook to acquire the young company. Today, Facebook's eagerness to gain control of the 'disappearing photos' application became more understandable with the announcement that Snapchat users now send 400 million self-destructing 'snaps' a day. That number is just shy of the amount of daily photos shared on Facebook (approximately 350 million) and Instagram (around 55 million) combined.

As reported by Business Insider and confirmed by CEO Evan Spiegel to Techcrunch, the staggering figure is the latest exponential increase for Snapchat since the start of the year. In late November 2012, users were sharing around 20 million photos every day. By June this year, that had increased ten-fold, and had reached 350 million by September. In contrast, Flickr - the 2nd largest dedicated public photo sharing site, after Instagram - only hosts around 3.5 million uploads every day.

Although the latest Snapchat figures are impressive, there are a few points to note. The 400 million Snapchat figure also includes that service's video messaging, and likely includes multiple copies of individual photos sent as group messages. However, as Business Insider points out, Snapchat still likely beats Facebook "on photo volume alone". Snapchat also has a much smaller userbase than Facebook, and their current traffic is only likely to increase as more and more users download and start using the application, which remains most popular among teenagers and young adults.

For more on Snapchat and why they're of so much interest to investors despite their lack of a revenue stream, read our quick guide to the service here.