This evening Facebook announced that they have surpassed the 10 billion photo milestone. In terms of files, that is over 40 billion files since there is 4 image sizes store for each individual photo. Doug Beaver provided some other interesting statistics including:

There are between 2 and 3 Terabytes of photos being uploaded daily.

Over 15 billion photos are served each day

Over one petabyte (1,024 Terabytes) of photos have been stored

Facebook is currently the largest online photo storage site, dominating even the highly popular photo sharing site: Flickr. This is an impressive number and it’s also impressive that the photos application is one of the few features on Facebook that rarely has significant issues. I know that I personally use the photos application heavily and based on the stats released tonight, it appears that just about every other user does as well.