img = [
["http://1","img/change1.gif","img01"],	//"リンク先URL","イメージのパス","Altテキスト" ※最後に ,(半角)を忘れずに
["http://2","img/change2.gif","img02"],	//"リンク先URL","イメージのパス","Altテキスト" ※最後に ,(半角)を忘れずに
["http://3","img/change3.gif","img03"]	//"リンク先URL","イメージのパス","Altテキスト" ※最終行は ,(半角)なし
];

function setimg() {
n = Math.floor(Math.random() * img.length);
document.write("<a href='",img[n][0],"'><img src='",img[n][1],"' border=0 alt='",img[n][2],"'></a>");

}