Code:
<html>
<head>
<script language="javascript" type="text/javascript"><!--
var imagesToDisplay = [<?php echo $image_array ?>];
var current = 0;
function nextImage() {
     if(++current > imagesToDisplay.length) current = 0;
     document.getElementById("myimage").src = imagesToDisplay[current];
}
function prevImage() {
     if(--current < 0) current = imagesToDisplay.length - 1;
     document.getElementById("myimage").src = imagesToDisplay[current];
}
onload = function() {
     document.getElementById("myimage").src = imagesToDisplay[0];
}
// --></script>
</head>
<body>
<img id="myimage" src="placeholder.png" /><br />
<a href="#" onclick="prevImage(); return false">Prev</a> | <a href="#" onclick="nextImage(); return false">Next</a>
</body>
</html>
This is just a general idea, though - remember to make it compatible with people who don't have Javascript (enabled).