searchIcon = new ImageIcon( \"searchIcon.png\" );
searchIconLabel = new JLabel();
searchIconLabel.setIcon(searchIcon);
....
searchHorizontalPanel.add( searchIconLabel
Your image file needs to be in the same directory as you are running the application from.
If its actually in the same directory as the class making the call then you can use:
searchIcon = new ImageIcon( getClass().getResource("searchIcon.png") );
If it is in some arbitrary location then you will need to specify the full path.