codice:
GridBagLayout grid = new GridBagLayout();
			GridBagConstraints constraints = new GridBagConstraints();
			constraints.insets.bottom = 5;
			constraints.insets.left = 5;
			constraints.insets.right = 5;
			constraints.insets.top = 5;
			constraints.fill = GridBagConstraints.BOTH;
								
			//labelPrincipale.setFont(new Font("Serif", Font.PLAIN, 20));			
			img = new ImageIcon("/images/logo2.png");
			labelPrincipale = new JLabel(img);
			constraints.gridx = 0;
			constraints.gridy = 0;
			constraints.gridwidth = 1;
			constraints.gridheight = 1;			
			grid.setConstraints(labelPrincipale, constraints);

contentPanelPrincipale = new JPanel();
			contentPanelPrincipale.setLayout(grid);
			contentPanelPrincipale.add(labelPrincipale, null);
ovviamente ho aggiunto altri elementi.....ma il problema è in label....vorrei visualizzare l'immagine....dove sbaglio???