import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Characters extends Thread {
   private int x;
   private int y;
   private JPanel frame;
   private Image im;
   public Characters(int a,int b) {
      x = a;
      y = b;
   }
   
   public Characters(int i, int j, JPanel frame,String path) {
      this(i,j);
      this.frame = frame;
      im = Toolkit.getDefaultToolkit().getImage (path);
   }

   @Override
   public void run() {
 for (int i = 0; i < 22; i = i + 1) {
       
          y += i;
          
         try {
            Thread.sleep(200);
            
         } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            System.out.println(i);
         }
      }
   
   }

   public void draw(Graphics graphics){
      graphics.setColor(Color.red);
      
      //qui metti l imagel
      //graphics.drawImage(.....)
      graphics.drawImage(im, x, y,frame);
   }
   
}

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.util.LinkedList;

import javax.swing.JFrame;


public class Main {

   private JFrame frame;
   private static final String[] paths = {"/Users/federicobarassi/NetBeansProjects/OK/src/ok/java1.gif",
      "/Users/federicobarassi/NetBeansProjects/OK/src/ok/java2.gif",
"/Users/federicobarassi/NetBeansProjects/OK/src/ok/java3.gif",
"/Users/federicobarassi/NetBeansProjects/OK/src/ok/java4.gif"};
   
   public Main() {
      frame =  new JFrame("Piove");
      frame.setSize(new Dimension(300,300));
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setLayout(new BorderLayout());
      frame.getContentPane().add(getFilledCPanel(),BorderLayout.CENTER);
      
      frame.setVisible(true);
   }
   
   private Component getFilledCPanel() {
      CustomPanel panel = null;
      LinkedList<Characters> list = new LinkedList<Characters>();
      for (int i = 0; i < paths.length; i++) {
         list.add(new Characters((i*80),0,panel,paths[i]));
      }
      panel = new CustomPanel(list);
      for (Characters characters : list) {
         characters.start();
      }
      return panel;
   }

   public static void main(String[] args) {
      new Main();
   }
}

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.util.LinkedList;

import javax.swing.JPanel;

public class CustomPanel extends JPanel {
   
   private LinkedList<Characters> list;
   
   public CustomPanel() {
      setSize(new Dimension(300,300));
      setBackground(Color.white);
   }

   public CustomPanel(LinkedList<Characters> a){
      this();
      list = a;
    
   }

    
      @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      for (Characters c : list) {
         c.draw(g);
      }
      repaint();
   }
}