Steps to Put a Selfie in your Snapchat Icon:

• Go to your profile page (swipe down while on the camera screen) and hit the ghost icon if you want a picture to show in the middle of your Snapchat icon.
• The camera will activate, and when you touch the capture button, Snapchat will take four photos of you, which will be converted into a GIF and used as your app's icon. Anyone who knows your Snapchat username will be able to see these photos.
• Don't forget to tap Done. At the bottom of the screen, there is a green button.

Read More: How does Snapchat work?