function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

    

    function fnSwap(myimg) {
        var newimg=myimg.src;        
        if (newimg.indexOf("_off") > 0) {
            newimg=newimg.replace("_off","_on");
        } else {
            newimg=newimg.replace("_on","_off");
        }
        myimg.src=newimg;
    }

    function fnSeeImage(imagename) {
        window.open("Pictures/gallery/" + imagename);
    }
    
    
    MM_preloadImages('images/btn_about_on.png','images/btn_porfolio_on.png','images/btn_contact_on.png','images/box_muneca_on.png');