how to upload the image into server?

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.Toast;

public class sde extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        loadtoUrl("http://
");
    }

    private void loadtoUrl(String string) {

        // TODO Auto-generated method stub
         try {
             String pathToOurFile = "/sdcard/tamil.PNG";
             FileInputStream fileInputStream = new FileInputStream(new File(pathToOurFile) );
             BufferedInputStream bis = new BufferedInputStream(fileInputStream,3000);
             byte[] bt=new byte[bis.available()];
            HttpURLConnection connection = (HttpURLConnection)new URL(string).openConnection();
             connection.setDoOutput(true);
             connection.setRequestMethod("POST");
             connection.connect();
            FileOutputStream input = (FileOutputStream) connection.getOutputStream();
            input.write(bt);
        } catch (MalformedURLException e) {
            Context context = null;
            int duration = 0;
            Toast.makeText(context, "erro in writing", duration);
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}