Shoot, Revert and Clear are buttons for the front desk to take photos of guests.
This function utilizes a standard USB webcam. When you first launch this app, it will ask if you want to allow it to use the camera. Always click NO unless you are setting up the front desk computer(s). If you are setting up a front desk computer and it does not ask to allow the camera, there will be a camera icon with a red x in showing in the address bar (far right in Chrome). Click on that and set it to allow use of the camera. After that, it should not ask again and on the Reservations page, you will only see the Clear button.
You can also upload a photo from your computer.
Remember to respect guest privacy and only use photography for internal security purposes.