$(document).ready(function(){
    $(window).load(function(){
        centerImages();
    });
});

function centerImages()
{
    $('span.slide-img, span.img, .mini-images li, dd.img a').each(function(){
        var boxHt = $(this).height();
        var img = $(this).children('img');
        var imgHt = img.height();
        if(imgHt < boxHt)
        {
            var margin = (boxHt - imgHt)/2;
            img.css('margin-top',margin+'px');
        }
    });
}