midlet中未显示图像

import java.io.IOException;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * @author jay
 */

public class WShop extends MIDlet implements CommandListener {

    /* Declare display variables*/
    private Form mainForm;
    private Display display;
    private Command OK,Exit,wView, mView, myView;

    /* */
    Categories categories = new Categories(this);
    Image image;


    public WShop() {

            /* initialize Screen and Command buttons that will
               be used when the application starts in the class constructor*/


            mainForm = new Form("Wind Shopper");

            OK = new Command("OK", Command.OK, 2);
            Exit = new Command("Exit", Command.EXIT, 0);
            wview= new Command("wview", Command.OK, 0);
            mview= new Command("mview", Command.OK, 0);

              try {
            /* retrieving the main image of the application*/
              image = Image.createImage("/main.png");
        } catch (IOException ex) {
            ex.printStackTrace();
        }



            mainForm.addCommand(OK);
            mainForm.addCommand(Exit);
            mainForm.addCommand(wView);
            mainForm.addCommand(mView);
            mainForm.setCommandListener(this);


    }

    public void startApp() {

         /* checks to see if the display is currently empty
          and then sets it to the current screen */

        if (display == null) {
            display = Display.getDisplay(this);
        }
            display.setCurrent(mainForm);
    }

 /* paused state of the application*/
    public void pauseApp() {
    }

   /* Destroy Midlet state*/
    public void destroyApp(boolean unconditional) {
    }

提前谢谢。