add: gtk_widget_set_usize ( list_button -> open_icon, 24, 24 );
context: static void gtk_list_button_init ( GtkListButton *list_button ){    list_button -> hbox = gtk_hbox_new ( FALSE, 6 );    list_button -> closed_icon = gtk_image_new_from_pixbuf ( gdk_pixbuf_new_from_xpm_data ( (const gchar **) book_closed_xpm ) );    list_button -> box = gtk_vbox_new ( FALSE, 0 );    gtk_box_pack_start ( GTK_BOX ( list_button -> hbox ), list_button -> box,			 FALSE, FALSE, 0 );    gtk_container_add ( GTK_CONTAINER(list_button -> box), list_button->closed_icon);    list_button -> open_icon = gtk_image_new_from_pixbuf ( gdk_pixbuf_new_from_xpm_data ( (const gchar **) book_open_xpm ));    list_button -> label = gtk_label_new ("") ;    gtk_label_set_line_wrap ( GTK_LABEL(list_button->label), TRUE );    gtk_box_pack_start ( GTK_BOX(list_button -> hbox), list_button -> label,			 FALSE, FALSE, 0 );    gtk_container_add ( GTK_CONTAINER(list_button), list_button -> hbox );    gtk_button_set_relief ( GTK_BUTTON (list_button), GTK_RELIEF_NONE );    g_signal_connect ( GTK_BUTTON(list_button), "clicked", 		       G_CALLBACK ( gtk_list_button_clicked ), NULL );    g_signal_connect ( GTK_WIDGET(list_button), "destroy", 		       G_CALLBACK ( gtk_list_button_destroy ), NULL );    gtk_widget_show ( list_button -> hbox );    gtk_widget_show ( list_button -> box );    gtk_widget_show ( list_button -> closed_icon );    gtk_widget_show ( list_button -> label );}