Take snapshots with your webcam by hitting the space bar on your keyboard.

snapshot.py

#***
# USAGE: python snapshot.py -l optionalCustomLabelHere
#***
#
# Take snapshots with your webcam.  
#   - Exit with ESC
#   - Snapshot with SPACE
#  
# NOTE: 
# -Change webcam src to your usb port number (Line 29)
# -With argument -l optionally pre-append a custom label
#  to your images (default: 'snapshot')

#Import the necessary packages
import cv2
import time
from datetime import datetime
from imutils.video import VideoStream
import argparse

#Construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-l", "--label",
	help="pre-append label to snapshots (optional)")
args = vars(ap.parse_args())

#Load cam
print("[INFO] Starting main video stream thread...")
vs = VideoStream(src=1).start() 
time.sleep(2.0)

while True:
    #Read the next frame from webcam
    image = vs.read()
    
    #Show the output image
    cv2.imshow("Image", image)

    #Grab key
    key = cv2.waitKey(1) & 0xFF

    #Exit with ESC
    if key == ord("\x1b"):
        print("[INFO] Escape hit, closing...")
        break
    
    #Snapshot with SPACE
    if key == ord(" "):
        img_label = args["label"] if args["label"] else 'snapshot'
        img_id = ''.join(i for i in str(datetime.now()) if i.isdigit())
        img_name = "{}_{}.png".format(img_label, img_id)
        cv2.imwrite(img_name, image)
        print("[INFO] {} saved!".format(img_name))

#Do a bit of cleanup
cv2.destroyAllWindows()
vs.stop()