无法将blob转换为图像？

I have an image in my local database at id 19 in column "profile_image". Now I want to fetch that image. I am using the codes below but they are not working. "profile_image" is LONGBLOB

require_once 'db.php';

$query = "SELECT * FROM users WHERE id = 19;";
$result = mysqli_query($conn, $query);
$row = mysqli_fetch_assoc($result);

echo '<img src="data:image/jpeg;base64,'.base64_encode( $row['profile_image'] ).'"/>';

mysqli_close($conn);