I am having problem uplaoding file, here are my codes: Any help? Thanks!

test.html

function insertPhoto()
{
    var description = document.getElementById('description').value;
    var image = document.getElementById('photo').value;
        var url = "ajax_insert.php?action=add&image="+image+"&description="+description;
    var ajaxRequest = ajax_obj();

            ajaxRequest.onreadystatechange = function() {
                        if(ajaxRequest.readyState == 4){

                document.getElementById("msgbox").innerHTML=ajaxRequest.responseText;

            }             
        }

        ajaxRequest.open("GET", url, true);
            ajaxRequest.send(null);

        return false;
}

<div align="center">
  <div class="top" >
    <div>
       Decription <input name="description" type="text" id="description" value="" maxlength="20" />
    </div>
    <div style="margin-top:5px" >
 Image
        <input name="photo" type="file" id="photo" value="" maxlength="20" />
    </div>
    <div class="buttondiv">
        <input name="button" type="button" value="Upload" onclick="return insertPhoto()" style="margin-left:-10px; height:23px"  /> 
        <span id="msgbox" style="display:none"></span>
    </div>
  </div>
</div>

ajax_insert.php

<?php
    mysql_connect('localhost','root','');
    mysql_select_db('priceless');
    define('DIR_IMAGE','images/');

    $image = $_GET['image'];
    $description = $_GET['description'];
    $dbtable = 'photos';
    $action = $_GET['action'];

    if($action == 'add'){
           $photo = '';
                if ($_FILES[$image]['name']) {
                    $aray = explode(".",$_FILES[$image]['name']);
                    $ext = $aray[count($aray)-1];
                    $photo = date('Ymdhis').'.'.$ext;
                    move_uploaded_file($_FILES[$image]['tmp_name'],DIR_IMAGE.$photo);
                } 

               $data = array(
              'image'=> $photo,
              'description'=> $description
               );
                $values = array();
                foreach($data as $show){
                    $values[] = $show;
                }        
              $query = "INSERT INTO ".$dbtable." (`".implode("`,`",array_keys($data))."`) values ('".implode("','",array_values($values))."')";
              if ($result= mysql_query($query) or die(mysql_error())) {        
                 echo "You have Sucessfully Upload Photo!";              
            }
    }
?>