var img = new Array;

img[0] = "<a href='URL'><img src='img/pickup01.jpg'></a>";
img[1] = "<a href='URL'><img src='img/pickup02.jpg'></a>";
img[2] = "<a href='URL'><img src='img/pickup03.jpg'></a>";
function random_img(){
var i = myrandom(img.length) - 1;
document.write(img[i]);
}
function myrandom(max){
        var v = max * Math.random();
        if(v == 0.0){v = 1;}else{v = Math.ceil(v);}
        return v;
}