SO jQuery Fiddle
Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5
by leongaban
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<div class="Image"><img src="/image1.jpg">1</div>
<div class="Image"><img src="/image2.jpg">2</div>
<div class="Image"><img src="/image3.jpg">3</div>
<div class="Image"><img src="/image4.jpg">4</div>
<div class="Image"><img src="/image5.jpg">5</div>
<div class="Image"><img src="/image6.jpg">6</div>
<div class="Image"><img src="/image7.jpg">7</div>
CSS
div.Image { display: none; }
JavaScript
var divs = $("div.Image").get().sort(function(){
return Math.round(Math.random())-0.5; //random so we get the right +/- combo
}).slice(0,4)
$(divs).appendTo(divs[0].parentNode).show();