import os

            cd = os.path.abspath('./')
            dir_name = os.listdir(cd)
            for i, file in enumerate(dir_name):
                os.rename(file, f'picture_{i}')
        
    

        
            import os
            folder = 'path_to_folder'
            for fileـname in os.listdir(folder):
                inـfileـname = os.path.join(folder,fileـname)
                if not os.path.isfile(inـfileـname): continue
                oldـbase = os.path.splitext(fileـname)
                newـname = inـfileـname.replace('.PNG', '.png')
                output = os.rename(inـfileـname, newـname)