$(document).ready(function () {
        $('.thumbnail').each(function(){
        // get height
        var height = $(this).height();
        // set slider height
        $(this).children('.slider').css({'height':height+'px'});
         $(this).hover(function () {
            $(this).children('.slider').slideToggle('fast');
        });
    });

.thumbnail {
    border: none;
    box-shadow: none;
    float: left;
    position: relative;
    margin: 5px;
    color: #333;
    overflow: hidden;
}