Add image thumbnails to a layout in a grid?

Question

I have a list of images. I need to add as small thumbnails to a frame. I currently have frame with SpringLayout. How can add thumbnails in some grid like fashio

Answer 1

This recently deleted question on the same topic prompted this example that uses randomly-sized, synthetic images to illustrate the effect of scaling to a particular SIZE in the largest dimension.

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.*;

/** @see https://stackoverflow.com/a/15982915/230513 */
public class Thumbnails {

    private static final int SIZE = 128;
    private static final Random r = new Random();

    // Get a randomly sized image
    static private Image getImage() {
        int w = r.nextInt(SIZE) + SIZE / 2;
        int h = r.nextInt(SIZE) + SIZE / 2;
        BufferedImage bi = new BufferedImage(
            w, h, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = bi.createGraphics();
        g2d.setPaint(Color.lightGray);
        g2d.fillRect(0, 0, w, h);
        g2d.setColor(Color.black);
        String s = w + "\u00D7" + h;
        int x = (w - g2d.getFontMetrics().stringWidth(s)) / 2;
        g2d.drawString(s, x, 24);
        g2d.dispose();
        return bi;
    }

    // Get a panel with an image scaled to SIZE in the largest dimension
    // https://stackoverflow.com/a/15961424/230513
    private static JPanel getPanel() {
        Image original = getImage();
        int w = original.getWidth(null);
        int h = original.getHeight(null);
        float scaleW = (float) SIZE / w;
        float scaleH = (float) SIZE / h;
        if (scaleW > scaleH) {
            w = -1;
            h = (int) (h * scaleH);
        } else {
            w = (int) (w * scaleW);
            h = -1;
        }
        Image scaled = original.getScaledInstance(w, h, Image.SCALE_SMOOTH);
        JPanel p = new JPanel(new GridLayout()){

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(SIZE, SIZE);
            }
        };
        p.add(new JLabel(new ImageIcon(scaled)));
        p.setBorder(BorderFactory.createLineBorder(Color.red));
        return p;
    }

    private static void createAndShowGUI() {
        JFrame f = new JFrame("PhotoAlbum55");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel = new JPanel(new GridLayout(6, 6));
        for (int i = 0; i < 6 * 6; i++) {
            panel.add(getPanel());
        }
        f.add(new JScrollPane(panel));
        f.pack();
        f.setSize(4 * SIZE, 4 * SIZE);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }
}