my netbeans not support user icon in JOtionPane

     hi need you help i try a lot of code to show image in JOptionPane put it just displays the message without the image , no error  in my code what is the problem plz i need you help and i use it with JOptionPane.showMessageDialog 
what ever i do no image is diplay in the jOptonPane

hi need you help i try a lot of code to show image in JOptionPane put it just displays the message without the image , no error in my code what is the problem plz i need you help and i use it with JOptionPane.showMessageDialog
what ever i do no image is diplay in the jOptonPane

 `public static void main( String [] args )
     {
     Icon icon = new ImageIcon( "ok.png" );
     String ttl = "example";
     String msg = "are you sure?";
     int ans = showConfirmDialog
     ( null, msg, ttl, YES_NO_OPTION, 0, icon );
     }
     0, icon );
     }
    }`