displaying image from database giving error

 string branchid = "";
    protected void Page_Load(object sender, EventArgs e)
    {
      branchid= Session["branchid"].ToString();
         
      Response.ContentType = "image/jpeg";
      Stream strm = ShowImage(branchid);
     
      byte[] buffer = new byte[4096];
      int byteSeq = strm.Read(buffer, 0, 4096);

      while (byteSeq > 0)
      {
           Response.OutputStream.Write(buffer, 0, byteSeq);
          byteSeq = strm.Read(buffer, 0, 4096);
      }
Image1.imageurl=byteSeq;
}


public Stream ShowImage(string branchid)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Safa"].ConnectionString);
        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();
        }
    }