Timer problem (setImage)

Hey everyone,

Here is the code I use for my timer:

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.awt.Color;  
import java.awt.Graphics;  
import java.awt.Font;

public class DisplayTime extends Game3
{
    
    public void displayTime()
    {
        if((System.currentTimeMillis() - WaveGame3.timeEnd) < 10000){
           int time = ((int)(System.currentTimeMillis() - WaveGame3.timeEnd)/1000);
           if(time == 1){
               GreenfootImage img = new GreenfootImage (100, 30);
               float fontSize = 20.0f;
               Font font = img.getFont();  
               font = font.deriveFont(fontSize);  
               img.setFont(font);
               img.drawString ("10", 200, 20);
               setImage(img);
           }
           if(time == 2){
               //return "9";
               GreenfootImage img1 = new GreenfootImage (100, 30);
               img1.drawString ("9", 200, 20);
               setImage(img1);
           }
           if(time == 3){
               //return "8";
           }
           if(time == 4){
               //return "7";
           }
           if(time == 5){
               //return "6";
           }
           if(time == 6){
               //return "5";
           }
           if(time == 7){
               //return "4";
           }
            if(time == 8){
               //return "3";
           }
           if(time == 9){
               //return "2";
           }
           if(time == 10){
               //return "1";
           }
        }
        //return "Wave in progress";
    }
}

Here:

               GreenfootImage img = new GreenfootImage (100, 30);
               float fontSize = 20.0f;
               Font font = img.getFont();  
               font = font.deriveFont(fontSize);  
               img.setFont(font);
               img.drawString ("10", 200, 20);
               setImage(img);

It should print "10" on the screen.. but instead nothing pops up.
Help please!