Unable to locate image file

/*
 * IconDisplayer.java is a 1.4 application that requires the following files:
 * images/rocketship.gif
 */

import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Rectangle;

import javax.swing.BorderFactory;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFrame;

/*
 * This component displays a single icon one or more times in a row. The images
 * are right-aligned, with 5 pixels padding in between. All but the rightmost
 * image are mostly transparent.
 */

public class IconDisplayer extends JComponent {
  private Icon icon;

  private int preferredNumImages = 2;

  private int pad = 5; //space between images

  private Rectangle iconRect = new Rectangle();

  private Rectangle clipRect = new Rectangle();

  public IconDisplayer(Icon icon, int preferredNumImages, int pad) {
    this.icon = icon;
    if (preferredNumImages > 0) {
      this.preferredNumImages = preferredNumImages;
    }
    if (pad >= 0) {
      this.pad = pad;
    }

    //Set a reasonable default border.
    if (this.pad > 0) {
      setBorder(BorderFactory.createEmptyBorder(this.pad, this.pad,
          this.pad, this.pad));
    }
  }

  public Dimension getPreferredSize() {
    if (icon != null) {
      Insets insets = getInsets();
      return new Dimension(icon.getIconWidth() * preferredNumImages + pad
          * (preferredNumImages - 1) + insets.left + insets.right,
          icon.getIconHeight() + insets.top + insets.bottom);
    } else {
      return new Dimension(100, 100);
    }
  }

  public Dimension getMinimumSize() {
    if (icon != null) {
      Insets insets = getInsets();

      //Return enough space for one icon.
      return new Dimension(icon.getIconWidth() + insets.left
          + insets.right, icon.getIconHeight() + insets.top
          + insets.bottom);
    } else {
      return new Dimension(0, 0);
    }
  }

  protected void paintComponent(Graphics g) {
    if (isOpaque()) { //paint background
      g.setColor(getBackground());
      g.fillRect(0, 0, getWidth(), getHeight());
    }

    if (icon != null) {
      //Draw the icon over and over, right aligned.
      Insets insets = getInsets();
      int iconWidth = icon.getIconWidth();
      int iconX = getWidth() - insets.right - iconWidth;
      int iconY = insets.top;
      boolean faded = false;

      //Copy the Graphics object, which is actually
      //a Graphics2D object. Cast it so we can
      //set alpha composite.
      Graphics2D g2d = (Graphics2D) g.create();

      //Draw the icons, starting from the right.
      //After the first one, the rest are faded.
      //We won't bother painting icons that are clipped.
      g.getClipBounds(clipRect);
      while (iconX >= insets.left) {
        iconRect.setBounds(iconX, iconY, iconWidth, icon
            .getIconHeight());
        if (iconRect.intersects(clipRect)) {
          icon.paintIcon(this, g2d, iconX, iconY);
        }
        iconX -= (iconWidth + pad);
        if (!faded) {
          g2d.setComposite(AlphaComposite.getInstance(
              AlphaComposite.SRC_OVER, 0.1f));
          faded = true;
        }
      }

      g2d.dispose(); //clean up
    }
  }

  /** Returns an ImageIcon, or null if the path was invalid. */
  protected static ImageIcon createImageIcon(String path) {
    java.net.URL imgURL = IconDisplayer.class.getResource(path);
    if (imgURL != null) {
      return new ImageIcon(imgURL);
    } else {
      System.err.println("Couldn't find file: " + path);
      return null;
    }
  }

  /**
   * Create the GUI and show it. For thread safety, this method should be
   * invoked from the event-dispatching thread.
   */
  private static void createAndShowGUI() {
    //Make sure we have nice window decorations.
    JFrame.setDefaultLookAndFeelDecorated(true);

    //Create and set up the window.
    JFrame frame = new JFrame("IconDisplayer");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Create and set up the content pane.
    ImageIcon ship = createImageIcon("rocketship.gif");
    IconDisplayer id = new IconDisplayer(ship, 5, -1);
    frame.getContentPane().add(id, BorderLayout.CENTER);

    //Display the window.
    frame.pack();
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    //Schedule a job for the event-dispatching thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
      }
    });
  }
}

I used JCreator and the build was not problem except,

Couldn't find file: rocketship.gif

Process completed.

Where to place the image folder? Please Advise. Thanks.