How to capture multiple images from Kinect V2 (ROS)?

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I created a small code that opens the Kinect IR camera. I can see the real time video that it shows, and I can capture one image. But how do I capture multiple images? It keeps on overwriting with image0

Here is my code so far:

#!/usr/bin/python

import roslib
import rospy
import cv2
import sys
from std_msgs.msg import String
from sensor_msgs.msg import Image
from cv_bridge import CvBridge, CvBridgeError

class PositionTracker:

    def __init__(self):
        # subscribe to kinect image messages
        self.sub = rospy.Subscriber("kinect2/qhd/image_ir", Image, self.image_callback, queue_size=1)
        self.bridge = CvBridge()

    def image_callback(self,data):

    try:
        cv_image = self.bridge.imgmsg_to_cv2(data)
    except CvBridgeError as e:
        print(e)
    cv2.imshow("Image window", cv_image)
c=cv2.waitKey(10)%256
if c == 10:
    h,w=cv_image.shape
    bitmap=cv2.cv.CreateImage((w,h), cv2.cv.IPL_DEPTH_16S, 1)
    cv2.cv.SaveImage('image'+str(click)+'.jpg',bitmap)
    click=click+1   
    #time.sleep(3)

def main(args):
    ic = PositionTracker()
    rospy.init_node('kinect_tracker')
    try:
        rospy.spin()
    except KeyboardInterrupt:
        print("Shutting down")
    cv2.destroyAllWindows()

if __name__ == '__main__':
    main(sys.argv)

I have tried to use the cv.SaveImage function. But it gives me an error. The above code opens the Kinect IR camera, but I want it to capture images and save it to the file system. How do I do it?