Image resizing on S3

main.py

import boto3
import botocore.exceptions
from PIL import Image
s3 = boto3.resource('s3')
bucket = s3.Bucket('ajs3')
size = 200, 200


def resize(filename):
    img = Image.open(filename)
    img.thumbnail(size)
    img.save('thumbnail_' + filename, 'PNG')


if __name__ == '__main__':
    for b in s3.buckets.all():
        print(b.name)

    for obj in bucket.objects.all():
        if '.png' in obj.key:
            fn = obj.key.split('/')[-1]
            try:
                bucket.download_file(obj.key, fn)
                resize(fn)
            except botocore.exceptions.DataNotFoundError as e:
                print e