How to downlaod an image file as a Zip file using C#.NET and J#

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using java.util;
using java.util.zip;
using java.io;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void lnkImage_Click(object sender, EventArgs e)
    {
       string FilePath = Server.MapPath("~/Image/");
       string FileDest = Server.MapPath("~/Image/");
       Zip(FileDest + "test.zip", FilePath + "pic.jpg");
    }

    private void Zip(string zipFileName, string sourceFile)
    {
        FileOutputStream filOpStrm = new FileOutputStream(zipFileName);
        ZipOutputStream zipOpStrm = new ZipOutputStream(filOpStrm);
        FileInputStream filIpStrm = null;
        filIpStrm = new FileInputStream(sourceFile);
        ZipEntry ze = new ZipEntry(Path.GetFileName(sourceFile));
        zipOpStrm.putNextEntry(ze);
        sbyte[] buffer = new sbyte[1024];
            int len = 0;

            while ((len = filIpStrm.read(buffer)) >= 0)
            {
                zipOpStrm.write(buffer, 0, len);
            }
    
        zipOpStrm.closeEntry();
        filIpStrm.close();
        zipOpStrm.close();
        filOpStrm.close();
        FileInfo file = new FileInfo(zipFileName); 
        Response.ClearHeaders();
        Response.ClearContent();
        Response.ContentType = "application/octet-stream";
        Response.AddHeader("Content-Disposition", "attachment; filename=" + "test.zip");
        Response.WriteFile(file.FullName);
        Response.End();
    }
}