Snapchat moves “upward of 150 million photos through the service on a daily basis.” Compared to Facebook’s Instagram, which moves 40 million photos a day, that is a lot of photos moved for such a new company. The app differs in the fact that images and videos are ephemeral rather than permanent, something that is attractive to teens and young adults.

via Snapchat – 4-30-13.

I suspected the ephemeral nature of Snapchat was a mirage but surprised at how simple they made it.  It is impossible to do what Snapchat claims because a simple screen grabbing app on the receiving end could also capture any photo or chat blurb before expiration.  I am surprised at how large Snapchat has become.  Here’s a pertinent blurb as to where the expired image files are stored.  The original article gets into more detail.

Each of the images within the received_image_snaps folder had a .nomedia extension appended to the end of the file name. For example, the name of the file figure 3 is “h1a81hurcs00h1365528700423.jpg.nomedia”. This was likely done to prevent the images stored within this directory from being placed in the gallery or from being scanned by the media store. AccessData’s Forensic Toolkit recognized the .nomedia extension that was appended to the end of the file name and ignored it, displaying the images.