change image function

I want to test this function with the python function
import image

# CREATE AN IMAGE FROM A FILE
img = image.Image("arch.jpg")

# CLEAR THE RED FROM ALL PIXELS
pixelList = img.getPixels()
count = 0
for p in pixelList: 
        p.setRed(0)
        img.setPixelAt(count,p)
	count+=1
win = image.ImageWin()
img.draw(win)

but the current problem is that the array I return does not contain the right pixel.
Any suggestions will be appreciated