resize all images in folder PIL python

gistfile1.txt

In [11]: #!/usr/bin/python                                                  
    ...: from PIL import Image                                              
    ...: import os, sys                       
    ...:                                                
    ...: path = "/var/www/gglobal/media/images/"        
    ...: dirs = os.listdir( path )                                       
    ...:         
    ...: def resize():
    ...:     for item in dirs:
    ...:         if os.path.isfile(path+item):
    ...:             im = Image.open(path+item)
    ...:             f, e = os.path.splitext(path+item)
    ...:             imResize = im.resize((200,100), Image.ANTIALIAS)
    ...:             imResize.save(f, 'png', quality=80)
    ...: 
    ...: resize()

why its not working for me?