how to rename uploaded image in php

Question

I got this code from w3schools, and tweaked it based on this one: Rename an uploaded file with PHP but keep the extension

Please help, what do I do so that the file extension will not be .tmp When I upload it to a folder on the server.

   <?php
    $filename=$_FILES["file"]["tmp_name"];
    $extension=end(explode(".", $filename));
    $newfilename=$prod .".".$extension;
    
    if ((($_FILES["file"]["type"] == "image/gif")
    || ($_FILES["file"]["type"] == "image/jpeg")
    || ($_FILES["file"]["type"] == "image/pjpeg"))
    && ($_FILES["file"]["size"] < 100000))
      {
      if ($_FILES["file"]["error"] > 0)
        {
        echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
        }
      else
        {
        echo "Upload: " . $_FILES["file"]["name"] . "<br />";
        echo "Type: " . $_FILES["file"]["type"] . "<br />";
        echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
        echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
    
        if (file_exists("../img/user_uploaded/" . $_FILES["file"]["name"]))
          {
          echo $_FILES["file"]["name"] . " already exists. ";
          }
        else
          {
          move_uploaded_file($filename,
          "../img/user_uploaded/" . $newfilename. $extension);
          echo "Stored in: " . "../img/user_uploaded/" .$newfilename. $extension;
          }
        }
      }
    else
      {
      echo "Invalid file, File must be less than 100Kb in size with .jpg, .jpeg, or .gif file extension";
      }
    ?>

Answer 1

$filename=$_FILES["file"]["tmp_name"];
$extension=end(explode(".", $filename));
$newfilename=$prod .".".$extension;

In the above code you are trying to get the temporary file's extension. Instead, you can take the extension of the original filename uploaded by the user.

$filename=$_FILES["file"]["name"];
$extension=end(explode(".", $filename));
$newfilename=$prod .".".$extension;

This will upload your file with the actual file extension.