How to retrieve images from a remote server in Android

The code below is what I use to retrieve images from a remote server, but the problem is the image doesn't show always. The image will only appear 5/7. Is there anything I am doing wrong? And also I am using LazyList (Lazy load of images in ListView) created by Fedor and I noticed that this never happens to it

ImageView mainImageView = (ImageView) findViewById(R.id.picture);
  ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);
  String imageurl = "http://www.yoururl/cutecats.png";

  ImageDownloadMessageHandler imageDownloadMessageHandler1= new ImageDownloadMessageHandler(progressBar, mainImageView);
  ImageDownlaodThread imageDownlaodThread = new ImageDownlaodThread(imageDownloadMessageHandler1,imageurl);
  imageDownlaodThread.sta开发者_如何学Crt();

 }

 class ImageDownlaodThread extends Thread {
  ImageDownloadMessageHandler imageDownloadMessageHandler;
  String imageUrl;

  public ImageDownlaodThread(ImageDownloadMessageHandler imageDownloadMessageHandler, String imageUrl) {
   this.imageDownloadMessageHandler = imageDownloadMessageHandler;
   this.imageUrl = imageUrl;
  }

  @Override
  public void run() {
   Drawable drawable = LoadImageFromWebOperations(imageUrl);
   Message message = imageDownloadMessageHandler.obtainMessage(1, drawable);
   imageDownloadMessageHandler.sendMessage(message);
   System.out.println("Message sent");
  }

 }

 class ImageDownloadMessageHandler extends Handler {
  ProgressBar progressBar;
  View imageTextView;

  public ImageDownloadMessageHandler(ProgressBar progressBar, View imageTextView) {
   this.progressBar = progressBar;
   this.imageTextView = imageTextView;
  }

  @Override
  public void handleMessage(Message message) {
   progressBar.setVisibility(View.GONE);
   imageTextView.setBackgroundDrawable(((Drawable) message.obj));
   imageTextView.setVisibility(View.VISIBLE);
  }

 }

 Drawable LoadImageFromWebOperations(String url) {
  Drawable d = null;
  InputStream is = null;
  try {
   is = (InputStream) new URL(url).getContent();
   d = Drawable.createFromStream(is, "src name");
  } catch (MalformedURLException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
  return d;
 }

 public void onBackPressed(){
    captains1.this.finish();
    overridePendingTransition(R.anim.hold, R.anim.fadeout);
    return;
 }

I made an Android open source class to manage pictures, maybe you can solve your problem with it: http://code.google.com/p/imagemanager/