YOU don't always want a photo to last forever, particularly when it is potentially embarrassing, or incriminating.
Enter Snapchat, a new app that acts as a texting service for photographs, but automatically deletes the images within seconds of their arrival.
Young Melburnians in particular have seized on its potential to share deliberately unflattering photographs of themselves - called ''selfies'' - in the knowledge they will generate a laugh and then quickly evaporate.
Launched earlier this year, the app has now seen more than 100 million photographs shared, often in rapid-fire ''chats''.
''The point of it is impermanence,'' said Monash University student Samantha Rowe, 23. ''It's a novelty, it's silly and a fun game people can play together.''
It also sounds like the perfect app for cheating politicians and cyber bullies, who could send compromising images without leaving tracks. But that's not quite the case: while the images do disappear from the receiver's phone, it is possible to store a screen shot of the image.
If that happens, a message alerts the sender, but by then the damage has already been done.