If you are using Construct 2, you need to post in C2 forum.
By "snapshot" do you mean a screenshot, or a photo from webcam?
If screenshot - use "System Snapshot Canvas" action, then in "System On Snapshot canvas" event load CanvasSnapshot into sprite.
If you need to take a photo from the webcam, see "Example: Webcam" template when you start a new project in Construct.