l'immagine non viene recuperata dal database utilizzando il percorso

Prova questo e confronta con il tuo, non so se funziona perché non l'ho testato, ma dovrebbe.

carica.php

include('config.php');

if ($_FILES["file"]["error"] > 0 )
{
    echo "Error: " . $_FILES["file"]["error"] . "<br>";
}
  else
{
    $filename  = basename($_FILES['file']['tmp_name']);
    $ext = pathinfo($_FILES["file"]["name"], PATHINFO_EXTENSION);

    $new_file_name = md5($filename).'.'.$ext;

    $final_save_dir = $_SERVER['DOCUMENT_ROOT'].DS.'www'.DS.'images'.DS;
    if(move_uploaded_file($_FILES['file']['tmp_name'], $final_save_dir . $new_file_name)) 
    {
        echo "Uploaded";
    } 
    else 
    {
       echo "File was not uploaded";
    }

    try
    {
        $stmt = $conn->prepare("INSERT INTO imgdb ( image ) VALUES ( ? ) ");
        $stmt->bindParam('1', $new_file_name, PDO::PARAM_STR);
        $conn->errorInfo();
        $stmt->execute();
    }
    catch (PDOException $e) 
    {
      echo 'Database Error'.$e->getMessage();
    }
}

fetch.php

<?php
include('config.php');
ini_set('display_startup_errors',1); 
ini_set('display_errors',1);
error_reporting(-1);

try
{
      $stmt = $conn->prepare("SELECT * FROM imgdb WHERE id = 3");
      $conn->errorInfo();
      $stmt->execute();

       while($row = $stmt->fetch(PDO::FETCH_ASSOC))
        {
            echo "<img src='images/".$row['image']."' height='100' width='100'/>"; 
        }
} 
catch (PDOException $e) 
{
     echo 'Database Error'.$e->getMessage();
}