how to display an default image when there is no image in database

Question

 
hi iam using asp.net with c#
i want to display an default image when there is no image in database
can you correct my code

 

 <%@ WebHandler Language="C#" Class="left1" %>

using System;
using System.IO;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;


using System.Web;

public class left1 : IHttpHandler
{

    public void ProcessRequest(HttpContext context)
    {
        string  branchid = "";
        
        if(context.Session["branchid"]!=null)
        

            branchid= context.Session["branchid"].ToString();
        else
            throw new ArgumentException("No parameter specified");

        context.Response.ContentType = "image/jpeg";
        Stream strm = ShowImage(branchid);
        byte[] buffer = new byte[4096];
        int byteSeq = strm.Read(buffer, 0, 4096);

        while (byteSeq > 0)
        {
            context.Response.OutputStream.Write(buffer, 0, byteSeq);
            byteSeq = strm.Read(buffer, 0, 4096);
        }
            }
public Stream ShowImage(string  branchid)
    {
        SqlConnection con = new SqlConnection(" Data Source=.; Initial Catalog=SafaView;User ID=sa;Password=nsg_ss_0103;");
        string sql = "SELECT imgleft1 FROM tblImages WHERE BranchId = @BranchId";
        SqlCommand cmd = new SqlCommand(sql, con);
        cmd.CommandType = CommandType.Text;
        cmd.Parameters.AddWithValue("@BranchId", branchid);
        con.Open();
        object img = cmd.ExecuteScalar();
                try
        {
            return new MemoryStream((byte[])img);
        }
        catch
        {
            return null;
        }
        finally
        {
            con.Close();
        }
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }
}

 
in page load
=========

 
string id = "";
protected void Page_Load(object sender, EventArgs e)
    {
      id= Session["branchid"].ToString();
        if (IsPostBack == false)
        {
            Image1.ImageUrl = "left1.ashx?BranchId="+id;
            Image2.ImageUrl = "left1old.ashx?BranchId="+id;
                    
        
           }

 
can you correct my code where i have place the code for displaying default image from folder images