Return Image from Generic Handler that stored in Sql Server Database Varbinary Database Asp.Net C#

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

using System;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Configuration;
public class GalleryImg : IHttpHandler {

    public void ProcessRequest(HttpContext context)
    {

        int id;

        if (context.Request.QueryString["id"] != null || context.Request.QueryString["id"] != "")
        {
            id = Convert.ToInt32(context.Request.QueryString["id"]);


            context.Response.ContentType = "image/jpeg";
            Stream strm = DisplayImage(id);
            byte[] buffer = new byte[2048];
            int byteSeq = strm.Read(buffer, 0, 2048);

            while (byteSeq > 0)
            {
                context.Response.OutputStream.Write(buffer, 0, byteSeq);
                byteSeq = strm.Read(buffer, 0, 2048);
            }

        }
    }

    public Stream DisplayImage(int id)
    {
        SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString.ToString());
        string sql = "SELECT Image FROM Tbl_Gallery WHERE id='" + id + "'";
        SqlCommand cmd = new SqlCommand(sql, connection);
        cmd.CommandType = CommandType.Text;
        connection.Open();
        object theImg = cmd.ExecuteScalar();
        try
        {
            return new MemoryStream((byte[])theImg);
        }
        catch
        {
            return null;
        }
        finally
        {
            connection.Close();
        }
    }


    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}