how to display a full screen images with python2.7 and opencv2.4

I am trying to create a sort of image player with python and opencv. The images that i show are the same resolution on my screen and i would like to display them bordless in a full screen mode (without the windows bar at the bottom and the image bar at the top).

I accept also advice in order to improve my "var" used a counter for displaying the images:)

Thanks

def main():
    var= 0
    while True:
        print 'loading images...'
        if var==0:
            img =  cv2.imread('2-c.jpg')
            var=var+1
        else:
            img =  cv2.imread('2-d.jpg')
        cv2.imshow("test",img)
        key=cv2.waitKey(0)
        if key==27:
            break

EDIT: I post an image and maybe i can explain myself better: as you can see there is still the blue bar on top