Try:
Label1.Text = Session["UserName"].ToString();
if (FileUpload1.HasFile)
{
fileName = FileUpload1.FileName;
filePath = Server.MapPath(Path.Combine("~/Images", Label1.Text, System.Guid.NewGuid().ToString() + fileName));
FileUpload1.SaveAs(filePath);
cmd.Parameters.AddWithValue("@image_Name", fileName);
But I'd suggest you might want to keep track of the GUID value if you want to find the file again...