It's not meant to be secure, it's meant to be delete by default. Even without an exploit you can take a screenshot of the picture you receive. However, default

It's not meant to be secure, it's meant to be delete by default. Even without an exploit you can take a screenshot of the picture you receive. However, defaults matter. Even if you're sending a private picture to someone you completely trust, if you do it by email or mms, they'll likely leave that picture lying around inadvertently for someone borrowing their phone to accidentally and embarrassingly stumble upon. With snapchat, the picture will be automatically deleted unless the recipient takes explicit measures to save it. THAT is the feature, not security.