Rename files in a given directory.

rename_files.py

import os


def rename_files(folder_name, new_file_name):
    """Rename images in a folder"""
    i = 0
    dir = "./" + folder_name
    for filename in os.listdir(dir):
        dst = new_file_name + str(i) + ".jpg"
        src = folder_name + "/" + filename
        dst = folder_name + "/" + dst
        os.rename(src, dst)
        i += 1

if __name__ == '__main__':
    rename_files("16", "boy_16_")