这是我的问题的解决方案。这个解决方案是Sergey和jewelsea的帮助。此解决方案位于javafx 2.2中。谢谢Sergey和jewelsea。

This is solution of my problem. This solution is help of Sergey and jewelsea. This solution is in javafx 2.2. Thanks Sergey and jewelsea.

public class TrySnapshot extends Application {

javafx.embed.swing.SwingFXUtils fXUtils;
BufferedImage bufferedImage = new BufferedImage(550, 400, BufferedImage.TYPE_INT_ARGB);
File file = new File("C:/Users/PC1/Desktop/Sample Images/test.jpg");
VBox vbox = null;

@Override
public void start(Stage primaryStage) {
    vbox = new VBox();
    Button btn = new Button();
    Image i = new Image("file:C:\\Koala.jpg");
    ImageView imageView = new ImageView();
    imageView.setImage(i);
    vbox.getChildren().add(imageView);
    vbox.setSpacing(10);
    btn.setText("Say 'Hello World'");
    btn.setOnAction(new EventHandler<ActionEvent>() {
        @Override
        public void handle(ActionEvent event) {
        // here we make image from vbox and add it to scene, can be repeated :)
       WritableImage snapshot = vbox.snapshot(new SnapshotParameters(), null);
           vbox.getChildren().add(new ImageView(snapshot));
            saveImage(snapshot);
            System.out.println(vbox.getChildren().size());
        }
    });


    Scene scene = new Scene(new Group(btn), 500, 400);

    primaryStage.setScene(scene);
    primaryStage.show();
}

private void saveImage(WritableImage snapshot) {
    BufferedImage image;
    image = javafx.embed.swing.SwingFXUtils.fromFXImage(snapshot, bufferedImage);
    try {
        Graphics2D gd = (Graphics2D) image.getGraphics();
        gd.translate(vbox.getWidth(), vbox.getHeight());
        ImageIO.write(image, "png", file);
    } catch (IOException ex) {
        Logger.getLogger(TrySnapshot.class.getName()).log(Level.SEVERE, null, ex);
    };
  }
 }