The way the application works is very simple: take a picture, add text to the image if you want, select the amount of time that the image will be available for, and send it to whoever you want. It’s that easy.
In order for the receiver to see the image, as a security measure, they will also need to have the application installed. If they take a screenshot of the image, you will receive a notification, so that way you can know if they have kept the image you sent or not.
A major objective of Snapchat, as you may have guessed, is sending risqué photos to a small number of contacts. Why? Because, in this way, the receiver can see the image but will not be able to keep it. Or, if they try to take a screenshot, you’ll still know.