Its working!!!! Thanks!!!!!!!

 

but now the Image bounces of the screen and doesnt come back.. what do i do??

 float myAlienX =20;
 float myAlienY = 20;
 float  speedX =10;
 float speedY =0;
 int hit = 0;
 int miss = 0;
 PImage img;
 
void setup()
{
 size (600,400);
 
 img = loadImage("Alien.png"); //load the image

}
 

 
 void draw ()
 {
  
   if(mousePressed) {hit = 0; miss = 0; }
  
   float paddle = 1000/(hit+10);
   if(myAlienX < 0 || myAlienY > width) speedX = -speedX ;
   if( myAlienY > height ){
     speedY = -speedY;
     float distance = abs(mouseX-myAlienX);
     if (distance < paddle) hit += 1;
     else miss +=1;
   } else   speedY += 1;
  
   myAlienX += speedX;
   myAlienY += speedY;
  
   background (100,200,500);
  // fill(200,100,50);
   fill (50,100,200);
  rect(mouseX-paddle, height-10, 2*paddle,10);
  image(img, myAlienX,myAlienY);
  fill (0);
  text ("hit : " + hit, 10 , 20);
  text ("miss : " + miss, 10 , 40);
 }