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];}}
}

window.onload = function(){ 
MM_preloadImages('assets/buttons/button-grey.gif','assets/buttons/button-green.gif','assets/buttons/BUTTON-red.gif','assets/buttons/button-black.gif','assets/buttons/button-yellow.gif','assets/buttons/BUTTON.gif','assets/buttons/menu-white.gif');
}