Resize image before uploading

Where Internet connection is slow, it takes too much time to upload images. Few days ago I was trying to upload some images in facebook and it seemed to take forever. The I wrote the following python program to reduce the image size (around 4MB to around 100 KB!):

import Image
import os, sys

# adjust width and height to your needs
width = 800
height = 600

for root, dirs, files in os.walk('./'):
    for name in files:       
        filename = os.path.join(root, name)
        if filename.endswith('jpg'):
            print filename
            imin = Image.open(filename)
            imout = imin.resize((width, height), Image.BICUBIC) 
            imout.save(filename)