var theImagesB = new Array()

theImagesB[0] = 'thumbs/b1.GIF'
theImagesB[1] = 'thumbs/b2.GIF'
theImagesB[2] = 'thumbs/b3.GIF'
theImagesB[3] = 'thumbs/b4.GIF'
theImagesB[4] = 'thumbs/b5.GIF'
theImagesB[5] = 'thumbs/b6.GIF'
theImagesB[6] = 'thumbs/b7.GIF'

var j = 0
var p = theImagesB.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = theImagesB[i]
}
var whichImageB = Math.round(Math.random()*(p-1));
function showImageB(){
document.write('<img src="'+theImagesB[whichImageB]+'">');
}