Update syntax and image uploading in PHP | Stackoverflow

<?php
    session_start();
    require_once '../assets/php/db.conn.php';
    require_once '../assets/php/func.main.php';
    date_default_timezone_set('Asia/Manila');
    if(!isset($_SESSION)){
        header('Location: ../');
    }
    error_reporting(E_ALL);
        ini_set('display_errors', 1);

    $_targetdir = "../assets/images/";
    $imgErrors = array();
    if($_POST){
        $title = strip_tags(trim($_POST['title']));
        $content = strip_tags(trim($_POST['content']));
        $articleid = genRand();
        $datetime = date('Y-m-d H:i:s');
        $imgName = null;

        if(empty($title)){
            $msgs = '
                <div class="alert alert-warning alert-dismissable">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Warning!</strong> Please add a title to your article!
                </div>
            ';
        } elseif(strlen($title) > 255){
            $msgs = '
                <div class="alert alert-warning alert-dismissable">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Warning!</strong> Your title is too long! The maximum length is only 255 characters!
                </div>
            ';
        } elseif(empty($content)){
            $msgs = '
                <div class="alert alert-warning alert-dismissable">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Warning!</strong> Please insert the content of your article!
                </div>
            ';
        }
        if(isset($_POST['imgUpload'])){
            $_targetfile = $_targetdir . basename($_FILES['imgUpload']["name"]);
            $filetype = pathinfo($_targetfile, PATHINFO_EXTENSION);

            $check = getimagesize($_FILES["imgUpload"]["tmp_name"]);
            if($check == false){
                array_push($imgErrors, 'File is not an image!');
            }
            if(file_exists($_targetfile)){
                array_push($imgErrors, 'Image already exists!');
            }
            if ($_FILES["imgUpload"]["size"] > 500000) {
                array_push($imgErrors, 'Image filesize is too big!');
            }
            if($filetype != "jpg" && $filetype != "png" && $filetype != "jpeg" && $filetype != "gif" ) {
                array_push($imgErrors, 'Sorry, your image file type is not supported!');
            }
            array_filter($imgErrors);
            if(empty($imgErrors)){
                if(move_uploaded_file($_FILES['imgUpload']['tmp_name'], $_targetfile)){
                    $imgName = $_FILES["imgUpload"]["name"];
                }
            }
        }

        # var_dump() every possible variables, still getting the results I want
        var_dump($articleid);
        var_dump($title);
        var_dump($imgName);
        var_dump($content);
        var_dump($datetime);

        #$sql = "INSERT INTO `posts` (`articleid`, `title`, `image`, `content`, `created_at`) VALUES (?,?,?,?,?)";
        #$insertstmt = $conn->prepare($sql);
        #$insertstmt->execute(array($articleid, $title, $imgName, $content, $datetime));
        #var_dump($insertstmt);

        $insertsql = "INSERT INTO `posts` (`articleid`, `title`, `image`, `content`, `created_at`) VALUES (:AID, :TLT, :IMG, :CNT, :TM)";
        $inserstmt = $conn->prepare($insertsql);
        $inserstmt->bindParam(':AID', $articleid);
        $inserstmt->bindParam(':TLT',$title);
        $inserstmt->bindparam('IMG',$imgName);
        $inserstmt->bindParam(':CNT',$content);
        $inserstmt->bindParam(':TM', $timestamp);

        if($inserstmt){
            $msgs = '
                <div class="alert alert-success alert-dismissable">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Success!</strong> Your article was posted successfully!
                </div>
            ';
        } else {
            $msgs = '
                <div class="alert alert-danger alert-dismissable">
                  <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
                  <strong>Error!</strong> The system encountered an error, please try again later!
                </div>
            ';
        }
    }
 ?>
<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.5.2/animate.min.css">
    <link rel="stylesheet" type="text/css" href="../assets/css/auth.css">
    <link rel="stylesheet" type="text/css" href="../assets/css/main.css">
    <link rel="stylesheet" type="text/css" href="../assets/css/imgUpload.css">
    <title>Dashboard | Stella Maris</title>
</head>
<body>
    <nav class="navbar navbar-default">
      <div class="container-fluid">
        <div class="navbar-header">
          <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
            <span class="sr-only">Toggle navigation</span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
          </button>
          <a class="navbar-brand" href="#">Stella Maris</a>
        </div>

        <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
          <ul class="nav navbar-nav">
            <li><a href="../"><span class="glyphicon glyphicon-home" aria-hidden="true"></span> Homepage</a></li>
            <li class="dropdown active">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false"><span class="glyphicon glyphicon-signal" aria-hidden="true"></span> Dashboard <span class="caret"></span></a>
              <ul class="dropdown-menu" role="menu">
                <li><a href="index.php"><span class="glyphicon glyphicon-home" aria-hidden="true"></span>  Home</a></li>
                <li class="divider"></li>
                <li><a href="#"><span class="glyphicon glyphicon-list-alt" aria-hidden="true"></span> New Post</a></li>
              </ul>
            </li>
          </ul>
          <ul class="nav navbar-nav navbar-right">
            <li class="dropdown">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false"><span class="glyphicon glyphicon-user" aria-hidden="true"></span> Administrator <span class="caret"></span></a>
              <ul class="dropdown-menu" role="menu">
                <li><a href="../auth/logout.php"><span class="glyphicon glyphicon-remove" aria-hidden="true"></span> Logout</a></li>
              </ul>
            </li>
          </ul>
        </div>
      </div>
    </nav>

    <div class="container">
        <form method="post" accept-charset="utf-8" enctype="multipart/form-data">
            <div class="form-group">
                <input type="text" name="title" placeholder="Your Article's Title" class="form-control" required maxlength="255">
            </div>
            <div class="form-group">
                <textarea name="content" placeholder="What's on your mind?" class="form-control" rows="5" required></textarea>
            </div>
            <div class="form-group">
            <div class="input-group">
                <span class="input-group-btn">
                    <span class="btn btn-default btn-file">
                        Browse… <input type="file" name="imgUpload" id="imgInp">
                    </span>
                </span>
                <input type="text" class="form-control" readonly>
            </div>
            <div class="imgUpload text-center">
                <img id='img-upload'/>
            </div>
            </div>
            <input type="submit" name="submit" value="Post" class="btn btn-primary">
            <input type="reset" name="reset" value="Clear Fields" class="btn btn-default">
        </form>
        <?php
            if(isset($msgs)){
                echo '<hr>';
                echo $msgs;
            }
            if(!empty($imgErrors)){
                echo '<hr>';
                foreach($imgErrors as $err){
                    echo $err;
                }
            }
        ?>
        <br><hr>
        <p>&copy; Stella Maris</p>
    </div>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js" type="text/javascript" charset="utf-8" ></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" type="text/javascript" charset="utf-8"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/wow/1.1.2/wow.min.js" type="text/javascript" charset="utf-8"></script>
    <script src="../assets/js/imgUpload.js" type="text/javascript" charset="utf-8"></script>
</body>
</html>