You should understand that users who see your messages can always save them, either by taking a screenshot or by using some other image-capture technology (whether that be software or even something as old-fashioned as a camera to take a photo of your device’s screen). If we’re able to detect that a recipient took a screenshot of a message you sent, we’ll try to notify you. But the same common sense that applies to the Internet at large applies to Snapchat as well: Don’t send messages that you wouldn’t want someone to save or share.
The new policy also walked back the idea that messages actually disappear:
We can’t guarantee that messages will be deleted within a specific timeframe. And even after we’ve deleted message data from our servers, that same data may remain in backup for a limited period of time. We also sometimes receive requests from law enforcement requiring us by law to suspend our ordinary server-deletion practices for specific information. Finally, of course, as with any digital information, there may be ways to access messages while still in temporary storage on recipients’ devices or, forensically, even after they are deleted.