$(document).ready(function() {
    $('#slideshow_prize').cycle({
        speed:     'slow',
        timeout:   6000,
        pager:     '#nav',
        pause:     false,
        slideExpr: 'img',
		before:     onBefore
    });
});

function onBefore() {
	// use the alt attribute of your img as the caption
    $('#carousel-caption').html($(this).attr('alt')); 
}