<?php
$imagefolder = "";
$images = GLOB($imagefolder . "/" . "*{.jpg,.jpeg,.png,.gif}", GLOB_BRACE);

foreach ($images as $img) {

	$file = $img;
	$fileparts = pathinfo($file);
	$path = $fileparts['dirname'] . "/newfiles/";
	$newfile = $path . date("Y-m-d", filemtime($img)) . "." . $fileparts['extension'];
	if (!file_exists($newfile)) {
		rename ($file, $newfile);
		$log = $path . "/log.txt";
		$data = "original file: {$file} to: {$newfile} status: Successful";
	} else {
		$data = "original file: {$file} to: {$newfile} status: Error, file exists";
	}

	file_put_contents($log, $data, FILE_APPEND); // create log file
}