private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        if (evt.getSource() == jButton1) {
            int returnVal = jFileChooser.showOpenDialog(MainJFrame.this);
            if (returnVal == JFileChooser.APPROVE_OPTION) {
                try {
                    BufferedImage bufferedImage = ImageIO.read(Files.newInputStream(Paths.get(jFileChooser.getSelectedFile().getAbsolutePath())));
                    this.image = bufferedImage;
                    this.aspectRatio = (double) image.getWidth(rootPane) / (double) image.getHeight(rootPane);
                    jLabel1.setIcon(new ImageIcon(image.getScaledInstance(jLabel1.getWidth(), (int) (jLabel1.getWidth() / this.aspectRatio), Image.SCALE_SMOOTH)));
                } catch (IOException ex) {
                    JOptionPane.showMessageDialog(this, "Can't load file.");
                }
            }
        }
    }

    private void formComponentResized(java.awt.event.ComponentEvent evt) {
        if (image != null) {
            jLabel1.setSize(this.getWidth(), (int) (this.getWidth() / this.aspectRatio));
            jLabel1.setIcon(new ImageIcon(image.getScaledInstance(jLabel1.getWidth(), (int) (jLabel1.getWidth() / this.aspectRatio), Image.SCALE_SMOOTH)));
        }
    }

    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MainJFrame().setVisible(true);
            }
        });
    }