$(document).ready(function(){
        
    $('.alink').children(".imgdot").html('<img src="medias/images/btn_menu_principal_point_of.gif" alt="btn_menu_principal_point_of" width="3" height="3" />');

    $('.alink').hover(
        function(){
            $(this).children(".imgdot").html('<img src="medias/images/btn_menu_principal_point_on.gif" alt="btn_menu_principal_point_on" width="3" height="3" />');
        },
        function(){
            $(this).children(".imgdot").html('<img src="medias/images/btn_menu_principal_point_of.gif" alt="btn_menu_principal_point_of" width="3" height="3" />');
        }
    );
        
});