how to retrieve image from database in php mysqli

// database connection
  $conn = mysqli_connect("localhost", "root", "", "student");
// Fetch image from database
	$img = mysqli_query($conn, "SELECT * FROM student_table");
     while ($row = mysqli_fetch_array($img)) {     
		
      	echo "<img src='images/".$row['imagename']."' >";   
      
    }