if (window.addEventListener) {
window.addEventListener("load", changeIcon, false);
} else if (window.attachEvent) {
window.attachEvent("onload", changeIcon);
}
function changeIcon()
{
var img = document.getElementsByTagName("img");
for( i = 0; i < img.length; i++ )
if( img[i].src == "http://blog.so-net.ne.jp/_img/cmn/profile_guest.gif" )
img[i].src = "http://cecilia.kuronowish.com/blog/image/guest.png"; // ←ここに画像ファイルを指定
}