Snapchat

The whole idea of Snapchat is take a photo, share it, and, poof, it's gone. But, there are certain circumstances when images could come back to haunt users, especially if law enforcement officials are involved.

The photo-sharing app penned a blog post on Monday about the situations in which the service is obliged to hand over "snaps" to the police. The central takeaway is that Snapchat can only give unopened snaps to the police -- because those are the snaps saved on its servers.

"Snaps are deleted from our servers after they are opened by their recipients," Snapchat's head of trust and safety Micah Schaffer wrote in the blog post. "So what happens to them before they are opened? Most of Snapchat's infrastructure is hosted on Google's cloud computing service, App Engine. Most of our data, including unopened Snaps, are kept in App Engine's datastore until they are deleted."

So, if law enforcement officials have a search warrant to see specific unopened snaps, the service is required by the federal Electronic Communications Privacy Act to hand them over.

Snapchat has given roughly a dozen snaps to the authorities since May 2013, according to Schaffer, which is a drop in the bucket compared with the 350 million snaps that are sent every day.

Besides unopened snaps, there is one exception to other snaps that can be retrievable: snaps within Stories. The photo sharing service launched Stories earlier this month with the idea of offering users 24 hours to repeatedly see a photo. Naturally, these images would stay on Snapchat's servers for that duration. According to Schaffer, these snaps within Stories are subject to the same legal requirements at unopened snaps.