python jpg thumbnail creator

thumbnailer.py

import os
from PIL import Image

output_dir = '.\\output'
thumbnail_size = (200,200)

if not os.path.exists(output_dir):
    os.makedirs(output_dir)

for dirpath, dnames, fnames in os.walk(".\\input"):
    for f in fnames:
        full_path = os.path.join(dirpath, f)
        if f.endswith(".jpg"):
            filename = 'thumbnail_{0}'.format(f) 
            new_path = os.path.join(output_dir, filename)
            
            if os.path.exists(new_path):
                os.remove(new_path)
                
            im = Image.open(full_path)
            im.thumbnail(thumbnail_size)
            im.save(new_path, "JPEG")