$("div.entryBody span.mt-enclosure-image").each(function(){
    var target_img = $('img',$(this));

    $(this).append('<span class="cap">' + target_img.attr('title')  + '</span>')
        .css({
            'display':'block',
            'margin':target_img.css('margin'),
            'float':target_img.css("float"),
            'width':target_img.attr('width')
        });

    target_img.css('margin','0 0 10px 0');
});