This sample code is for Raspberry Pi Security Camera with Motion Detector tutorial(image).

security_image.py

from gpiozero import MotionSensor
from picamera import PiCamera
import time
from time import sleep

pir = MotionSensor(4)
camera = PiCamera()
camera.rotation = 180

while True:
    pir.wait_for_motion()
    print("Motion detected!")
    camera.start_preview(fullscreen=False, window = (1250,10,640,480))
    filename = "/home/pi/Desktop/" + (time.strftime("%y%b%d_%H:%M:%S")) + ".jpg"
    camera.capture(filename)
    pir.wait_for_no_motion()
    camera.stop_preview()