When you take photos or videos to send to friends on Snapchat, you can’t unsend them after they’ve been sent. The only thing you can do is delete the message, but there’s no 100 percent guarantee that the recipient won’t see it.
Since chat messages are automatically deleted once you leave the chat, the following instructions assume you have a chat open with a friend or group at that time.
In the chat tab, tap and hold the message you sent and want to delete.
Tap the purple Delete button to confirm you want to delete it. Keep in mind that your friends in the chat will be able to see that you deleted something.