How to upload multiple files using ajaxfileupload in asp.net to database?

Hi guys! I'v been trying to upload six images using ajaxfileupload in asp.net to MSSQL server but it always save only one image. 

Here is the aspx code:

<div class="divTableBody">
<div class="divTableRow">
<div class="divTableCell"><strong>Thumbnail Images:
</strong></div>
<div class="divTableCell">
<asp:AjaxFileUpload ID="itemFileUpload3"
runat="server"
OnUploadComplete="itemImage3OnUpload"
MaximumNumberOfFiles="10" Width="420px"/>
<p id="itemImage3Validate"></p>
</div>
</div>
</div>

And here is the aspx.cs code:

protected void itemImage3OnUpload(object sender, AjaxFileUploadEventArgs
e)
{

string filename = e.FileName;
Session["PicturePath3"] = filename;
if (itemType1.Checked)
{
itemFileUpload3.SaveAs(Server.MapPath("~/Images/Sub Images/") +
filename);
}
else if (itemType2.Checked)
{
itemFileUpload3.SaveAs(Server.MapPath("~/Images/Sub Images/") +
filename);
}

}

protected void itemSaveButton_Click(object sender, EventArgs e)
{

try
{

string itemThumbImage = Session["PicturePath3"].ToString();


int itemInstrumentID =
ConnectionClassGuitarItems.GetItemIDByNameAndModel
(item_brandId,item_model);

var subImg = new thumbnailImage
{
instrumentId = itemInstrumentID,
subimages = itemThumbImage
};

ConnectionClassGuitarItems.AddThumnailImage(subImg);
ScriptManager.RegisterStartupScript(this.Page,this.GetType()
, "msgboxScc", "btnClickSuccess();", true);

ClearTextFields2();

}
catch (Exception)
{
ScriptManager.RegisterStartupScript(this.Page, this.GetType()
, "msgboxErr", "btnClickFail();", true);
}


}

And then I will add my images using this code:

public static void AddThumnailImage(thumbnailImage subImg)
{
using (MusicStoreDBEntities obj = new MusicStoreDBEntities())
{

obj.thumbnailImages.Add(subImg);
obj.SaveChanges();
}
}