Complex sentence: In May 2012,25 images were being sent per second and, as of November 28,2012, users had shared over one billion photos on the Snapchat iOS app, with 20 million photos being shared per day.
Split into simpler sentences: In May 2012,25 images were being sent per second. As of 28 November 2012, users had shared over one billion photos on the Snapchat iOS app, with 20 million photos being shared per day.