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.
Snapchat is a useful app for communicating with your friends quickly, easily, and visually. At the end of the day, why send a lot of text when you can make yourself clear with a single picture instead?