if (isset($_POST['submit'])) {
    $extension = explode('.', $_FILES['image']['name']);
    $origname = $extension[0];
    $image = $origname . '-' . rand(10000, 99999) . '.' . $extension[1];
    $file_loc = $_FILES['image']['tmp_name'];
    $folder = "../image/banner/";
    move_uploaded_file($file_loc, $folder . $image);
    $query = mysqli_query($conn, "insert into banner(image) VALUES('$image')");
    $_SESSION['msg'] = " Successfully Added your banner Thank you!!";
}

$fileinfo = @getimagesize($_FILES["file-input"]["tmp_name"]);
$width = $fileinfo[0];
$height = $fileinfo[1];

For Size

$_FILES["file-input"]["size"]