make my image switch

import greenfoot.*;

/**
 * Write a description of class Gohan here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Gohan extends Actor
{
     private int health = 900000; //its over 9000   
    public void setHealth(int points) {
        health += points;  
    }
    public int getHealth() {
        return health;
    }
    private GreenfootImage image1;
    private GreenfootImage image2;
    private GreenfootImage image3;
    private GreenfootImage image4;
    private GreenfootImage image5;
    private GreenfootImage image6; 
    private GreenfootImage image7;
    private GreenfootImage image8;
    public Gohan() 
    {
        image1 = new GreenfootImage("gohan.png"); 
        image2 = new GreenfootImage("gohanstep.png");
        image3 = new GreenfootImage("gohanstep2.png");
        image4 = new GreenfootImage("powerattack.png");
        image5 = new GreenfootImage("gohanpunch.png");
        image6 = new GreenfootImage("Gohankick1.png");
        image7 = new GreenfootImage("HealthBar.png");
        image8 = new GreenfootImage("Gpowerup.png");
        setImage(image1); 
    }/**
     * Act - do whatever the Gohan wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public void act() 
    {
       checkKeypress ();
}
    public void checkKeypress() 
    {
        if (Greenfoot.isKeyDown("left"))
        {
            move(-30);
           if ( getImage() == image1 ) 
            {   setImage(image2);
            }
            else
                {if ( getImage() == image8 ){}
                 else{   setImage(image1);
                      
                    }
        }
    }
        if (Greenfoot.isKeyDown("right"))
             {    move (30);
                 if ( getImage() == image1 ) 
            {   setImage(image2);
            }
            else  setImage(image1);
        }

        if (Greenfoot.isKeyDown("s"))
        {
                setImage(image3);
                hitEnemy();
        }
        else if ( getImage() == image3)
        {
            setImage(image1);}
                if (Greenfoot.isKeyDown("z"))
        {
                setImage(image3);
                hitEnemy();
        }
                if (Greenfoot.isKeyDown("x"))
        {
                setImage(image6);
                hitEnemy();
        }
            else if ( getImage()== image6)
            {setImage(image1);}
                if (Greenfoot.isKeyDown("a"))
        {   
                setImage(image5);
                hitEnemy();
        }
        else if ( getImage()== image5)
            {setImage(image1);}
                if (Greenfoot.isKeyDown("space"))
        {   
                setImage(image4);
                hittingEnemy();
        }
        else if ( getImage() == image4 )
            {setImage(image1);}
        if (health<=0)
        {
            Greenfoot.playSound("cellyelling.wav");
            getWorld().removeObject(this);
        } 
        }
        private void hitEnemy() {
        Cell cell = (Cell) getOneObjectAtOffset(0, 0, Cell.class);
        if (cell != null) {
            cell.setHealth(-1001);
            cell.move(30);
        } 
    }
        private void hittingEnemy() {
        Cell cell = (Cell) getOneObjectAtOffset(0, 0, Cell.class);
        if (cell != null) {
            cell.setHealth(-3000);
            cell.move(200);
        }
    }      
}
}

import greenfoot.*;

/**
 * Write a description of class Cell here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Cell extends Actor
{
    /**
     * Act - do whatever the Cell wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    //this works
    public int health = 900000;
     
    public void setHealth(int points) {
        health += points;  
    }
    public int getHealth() {
        return health;
    }
    private GreenfootImage image1;
    private GreenfootImage image2;
    private GreenfootImage image3;
    public Cell()
    {
      image1 = new GreenfootImage("Cell.png"); 
      image2 = new GreenfootImage("Cellpunch.png");
      image3 = new GreenfootImage("Cellpunch2.png");
    }

    public void act() 
    {
                    if (Greenfoot.isKeyDown("a"))
        {   
                setImage(image1);
        }
                    if (Greenfoot.isKeyDown("s"))
        {   
                setImage(image1);
        }
                    if (Greenfoot.isKeyDown("z"))
        {   
                setImage(image1);
        }        
            if ( Greenfoot.getRandomNumber(100) < 10 ) 
        {
            setImage(image1);
            move(20); 
        }
        if ( Greenfoot.getRandomNumber (100) < 40 )
        {
            move(-60);
        }
        if ( Greenfoot.getRandomNumber (100) < 90 )
        {   if ( getImage() == image1 ) 
                {       setImage(image2);
                }
               if (Greenfoot.isKeyDown("shift"))
                {}
                else
                {
                hitEnemy();
        }
    }
        if ( Greenfoot.getRandomNumber (100) < 60 )
        {   
                setImage(image3);
                if (Greenfoot.isKeyDown("shift"))
                {}
                else
                {
                hitEnemy();
        }
        }if (health<=0)
        {
        }
        dead();
    }    
   private void dead() {
       if (health <=0)
       {
           Greenfoot.playSound("gohanyelling.wav");            
           getWorld().removeObject(this);
        }
    }
    private void hitEnemy() {
        Gohan gohan = (Gohan) getOneObjectAtOffset(0, 0, Gohan.class);
        if (gohan != null) {
            gohan.setHealth(-3000);
            gohan.move(-100);
        }
    }
}