php - How can i give a unique random name of the pictures when they are being uploaded? -

this question has answer here:

• upload images through php using unique file names 4 answers

here's code: need give random name photos when being uploaded, don't know how, please help.

<?php    if (isset($_post['submit'])) {      $validextensions = array("jpeg", "jpg", "png");      $temporary = explode(".", $_files["file"]["name"]);      $file_extension = end($temporary);        if ((($_files["file"]["type"] == "image/png") || ($_files["file"]["type"] == "image/jpg") || ($_files["file"]["type"] == "image/jpeg")              ) && ($_files["file"]["size"] < 1000000000000000000000000000000000000000000000000000000)//approx. 100kb files can uploaded.              && in_array($file_extension, $validextensions)) {            if ($_files["file"]["error"] > 0) {              echo "return code: " . $_files["file"]["error"] . "<br/><br/>";          } else {                echo "<span>vasa slika je uspesno prikacena...!!</span><br/>";              echo "<br/><b>ime od vasa slika:</b> " . $_files["file"]["name"] . "<br>";              echo "<b>tip:</b> " . $_files["file"]["type"] . "<br>";              echo "<b>velicina:</b> " . ($_files["file"]["size"] / 1024) . " kb<br>";                   if (file_exists("upload/" . $_files["file"]["name"])) {                  echo $_files["file"]["name"] . " <b>vec postoji.</b> ";              } else {                  move_uploaded_file($_files["file"]["tmp_name"], "upload/" . $_files["file"]["name"]);                  $imgfullpath = "http://".$_server['server_name'].dirname($_server["request_uri"].'?').'/'. "upload/" . $_files["file"]["name"];                  echo "<b>link ka vasu sliku:</b><a href = '$imgfullpath' target='_blank'> " .$imgfullpath.'<a>';                }            }      } else {          echo "<span>***niste odabrali sliku !!!***<span>";      }  }  ?> 

the question is: how can give unique random name of pictures when being uploaded ? tittle says.

thanks.

first, read this: https://stackoverflow.com/a/2562877/2266583

then information in mind:

echo md5($path_parts['filename'] . time()) . $path_parts['extension']