python如何读取像素值

import Image  
import sys   
im = Image.open(sys.argv[1])  
width = im.size[0]  
height = im.size[1]  
print "/* width:%d */"%(width)  
print "/* height:%d */"%(height)  
count = 0   
for h in range(0, height):  
  for w in range(0, width):  
    pixel = im.getpixel((w, h))   
    for i in range(0,3):  
      count = (count+1)%16  
      if (count == 0):   
        print "0x%02x,/n"%(pixel[i]),  
      else:  
        print "0x%02x,"%(pixel[i]),