#Reduce the blue and green in an image.
def makeRedder():
  pic=makePicture(pickAFile())
  pxls=getPixels(pic)
  #pxls is an array---a long list--- of the 
  #pixels in pic
  for px in pxls:
    setGreen(px,0.7*getGreen(px))
    setBlue(px,0.7*getBlue(px))
  #the for statement is something new!
  show(pic)