Extract images in different folders to single folder

sieve_images_to_single_folder.py

import os
from shutil import copyfile

train_path = '/DATA1/datasets/ILSVRC2012_img_train/imagenet'
destination_path = '/DATA1/datasets/ILSVRC2012_img_train/imagenet_all_images'

i = 0
for path, dir_name, file_names in os.walk(train_path):
    i += 1

    if len(dir_name) == 0:
        for file_name in file_names:
            file_src = os.path.join(path, file_name)
            file_dest = os.path.join(destination_path, file_name)
            copyfile(file_src, file_dest)