You may want to think twice (or thrice, for some) before you send that next Snapchat: a forensics researcher has discovered that for Android users, Snapchat doesn't delete its photos, it just hides them. Meaning: they are RECOVERABLE. 

The researcher, Richard Hickman, experimented with the photo-deletion* app (a very big asterisk there) using a Samsung Galaxy S3.  He concluded that "images that are sent via Snapchat are indeed recoverable, and do not 'disappear forever.'" This is because Snapchat uses the suffix ".nomedia" for its photos, which other apps will not open—think of it as the ".jpg" at the end of your image files. So, because other apps won't open this kind of file, you're in the clear right?  No. With the right tools and time, if someone wanted to access the folders where these photos and video are stored, they'd have to look for the "com.snapchat.android_preferences.xml" file within their phone. Hickman retrieved his Snapchat photos by using Access Data's Forensics Toolkit version 

Snapchat usage is still high and climbing higher, so problems like this probably won't make much of a dent in its popularity. But like most things in our social media lives, choose wisely before you commit to that send button.