Snapchat is not just used for sending photos to your friends when you are bored; it has gained huge popularity in the erotic department as well - which is good news for us horny guys and girls.
Even the company itself does not store your 1-week old photos in their servers! However, like anything online, its necessary to exercise caution when sharing pictures as you do not know if the receiver is using other third-party apps to save your images.