Allow user to upload/change profile image from a default image in php

So I want the users to be able to upload profile images in which they will be able to be seen when making posts/commenting or replying to other comments/posts. So far the user is able to upload an image in which the image gets stored in a uploads/ folder, but once I reload the profile page the image is not there anymore and it is not currently being saved to the user. I also think that the image is not saved nor connected to the specific user when uploading. Heres how the codes look:

profile.php

<?php
    require 'header.php';
    require 'upload.php';
    if(!isset($_SESSION["username"])){header("location: login.php");}
    

?>
<body>


<div class="tab">
  <button class="tablinks" onclick="openTab(event, 'User Profile')" id="default">User Profile</button>
  <button class="tablinks" onclick="openTab(event, 'Security')">Security & Privacy</button>
  <button class="tablinks" onclick="openTab(event, 'Tokyo')">Tokyo</button>
  <button class="tablinks" onclick="openTab(event, 'Tokyo')">Tokyo</button>
</div>

<div id="User Profile" class="tabcontent">
<?php
    echo '<img src="'.$target_file.'">';
   if(isset ($_SESSION["username"])){
   echo "<h3 id='username'>" . $_SESSION["username"] . "</h3>";
   
        }
    ?>
      <?php
        if(isset ($_SESSION["role"])){
          echo "<h4>" . $_SESSION["role"] . "</h4>";
            }
            
           
          ?>
              <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" enctype="multipart/form-data">
              <input type="file" name="fileToUpload" id="fileToUpload">
              <button type="submit" name="submit" value="Upload Image">Upload Image</button>
              </form>

upload.php

<?php
require_once 'header.php';
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));

// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
  $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
  if($check !== false) {
    echo "File is an image - " . $check["mime"] . ".";
    $uploadOk = 1;
  } else {
    echo "File is not an image.";
    $uploadOk = 0;
  }
}

// Check if file already exists
if (file_exists($target_file)) {
  echo "Sorry, file already exists.";
  $uploadOk = 0;
}

// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
  echo "Sorry, your file is too large.";
  $uploadOk = 0;
}

// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
  echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
  $uploadOk = 0;
}

// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
  echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
  if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
    echo "The file ". htmlspecialchars( basename( $_FILES["fileToUpload"]["name"])). " has been uploaded.";
  } else {
    echo "Sorry, there was an error uploading your file.";
  }
}

?>

As far as I've understood this, it would not be good to save the images to the database as it would make the website/database a lot slower. However, I would still need to reference the image somehow to the specific user I assume? I am quite new at this. This is how the table structures look in MYSQL:

CREATE TABLE IF NOT EXISTS `users` (
  `users_id` int(11) NOT NULL AUTO_INCREMENT,
  `users_username` tinytext
  `users_password` longtext
  `users_email` tinytext
  `create_datetime` datetime
  `users_role` tinytext
  `gender` tinytext
  PRIMARY KEY (`users_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=6 ;

CREATE TABLE IF NOT EXISTS `profileimg` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `users_id` int(11) NOT NULL,
  `status` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=14 ;

Any tips on how I could improve this? Thank you guys!