but00 = new Array('/i/living-england-000.jpg','Battersea power station');
but01 = new Array('/i/living-england-001.jpg','Battersea power station');
but02 = new Array('/i/living-england-002.jpg','Battersea power station');
but03 = new Array('/i/living-england-003.jpg','Battersea power station');
but04 = new Array('/i/living-england-004.jpg','Battersea power station');
but05 = new Array('/i/living-england-005.jpg','Battersea power station');

var butArr = new Array(but00, but01, but02, but03, but04, but05);

createGifAd = function(adRef){
			document.write('<img src="'+ adRef[0] +'" border="0" alt="adRef[1]"></a>');
}

var butRand = Math.floor(Math.random()*butArr.length); 

document.write('<span style="display:block;text-align:center">');
createGifAd(butArr[butRand]);
document.write('</span>');