function switch1(div) {
var option=['imagenhead1','imagenhead2','imagenhead3','imagenhead4','imagenhead5','imagenhead6','imagenhead7'];
for(var i=0; i<option.length; i++) {
if (document.getElementById(option[i])) {
obj=document.getElementById(option[i]);
obj.style.display=(option[i]==div)? "block" : "none";
}
}
}

window.onload=function () {switch1('imagenhead1');}

function switch2(div) {
var option=['imagenint1','imagenint2','imagenint3','imagenint4','imagenint5','imagenint6','imagenint7'];
for(var i=0; i<option.length; i++) {
if (document.getElementById(option[i])) {
obj=document.getElementById(option[i]);
obj.style.display=(option[i]==div)? "block" : "none";
}
}
}

window.onload=function () {switch2('imagenint1');}