import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class GrayImage extends JPanel {
public GrayImage() {
}
public void paint(Graphics g) {
Image myImage = new ImageIcon("yourImage.png").getImage();
BufferedImage bufferedImage = new BufferedImage(myImage.getHeight(this), myImage.getWidth(this), BufferedImage.TYPE_BYTE_GRAY);
Graphics gi = bufferedImage.getGraphics();
gi.drawImage(myImage, 0, 0, null);
gi.dispose();
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(bufferedImage, null, 0, 0);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.add(new GrayImage());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400,400);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}