#Now we write a program that
#modifies every pixel in a picture.
#This one removes the blue and green
#components of every pixel.
def makeRed():
  pic=makePicture(pickAFile())
  pxls=getPixels(pic)
  #pxls is an array---a long list--- of the 
  #pixels in pic.  Don't try to print it!
  for px in pxls:
    setGreen(px,0)
    setBlue(px,0)
  #the for statement is something new!
  show(pic)