Take a Live Photo in FaceTime on Mac
When you’re on a FaceTime video call with one or more people, you can take a Live Photo of a participant to capture a moment from the call. See FaceTime Live Photo requirements.
Set up FaceTime for Live Photos
Go to the FaceTime app
on your Mac.Choose FaceTime > Settings, then click FaceTime.
Select the FaceTime Live Photos checkbox. (This option is unavailable during a call.)
Note: When you select this option, you’re also allowing others to take Live Photos of you.
Take a Live Photo
Before taking a Live Photo, make sure you’ve opened the Photos app 
at least once, so Live Photos can automatically be saved in your Photos library. (The Photos app doesn’t need to be open when you take a Live Photo.)
Go to the FaceTime app
on your Mac.Do one of the following during a video call:
In a one-on-one call: Select the FaceTime window.
In a group call: Double-click the tile of the person you want to take a Live Photo of.
Click
When you take a Live Photo of someone, or someone takes a Live Photo of you, you both receive a notification.
Note: If you can’t take a Live Photo of someone, make sure both of you have set up FaceTime for Live Photos.