i'm fairly new to processing and i really need to be able to create these four images from the string in my class Idea. but is there a way to make it so that the images will appear only once the mouse is clicked? at the moment i can only get them to be all created at the same time.

Idea[] ideas=new Idea[4];
String[] files = {"arch.jpg","arch1.jpg","arch2.jpg","arch3.jpg"};
PImage world;

PImage[] images = new PImage[files.length];


int maxIdeas = 4;
int imageIndex =0;
int fade=255;



void setup() {
  size(800, 800);
  imageMode (CENTER);
  //img = loadImage("arch.jpg");
  frameRate(30);
  smooth();
  for (int i = 0; i < images.length; i ++ ) {
    images[i] = loadImage( files[i] );
  }
  
  for (int create=0;create<4;create++)
  {
    ideas[create]=new Idea(width/2, height/2,100,0.8);
  }
}
 


// ------------------------------------------------------------------------------ Main methods
void draw() {
  background(0);
  fill(0, fade);
  world= loadImage ("world.png");
  image(world,width/2,height/2);
  //ellipse (width/2, height/2, 400, 400);
  
 
 
  for (int display=0;display<4;display++)
  {
    ideas[display].drawIdea();
    ideas[display].move();
  }
  }

class Idea
{
  float ideax;
  float ideay;
  float change = 1;
  int imageIndex=0;
  int r;
  int[] changeimage = {1,2,3,4};

  float movex=random(1, 4);
  float movey=random(1, 4);

  Idea(float x, float y, float speed, float _diameter)
  {
    ideax=x;
    ideay=y;
  }
 

  void drawIdea()
  {

    pushMatrix();
    translate(ideax, ideay);//controls the position
    image(images[imageIndex],20,20);
    //image(img, 20, 20);
    //fill (colour);
    //quad(10,20, 70,50, 60,80, 20,80);
    //ellipse(0, 0, 80, 80); 
    popMatrix();
  }

  void move()
  {
    ideax+=movex;
    ideay+=movey;

    if (ideax+70 > width) {//right
      ideax = width-70;
      movex*=-1;
    }
    else if (ideax-30<0) //left
    {
      ideax = 30;
      movex *= -1;
    }
    if (ideay+70>height)//bottem
    {
      ideay=height-70;
      movey*=-1;
    }
    else if (ideay-30<0)//top
    {
      ideay=30;
      movey*=-1;
    }
  }
}