Simple full-size preview popup.

thumb-popup.js

    var thumbModal = function (thumbs, fullImgContainer) {
        for (var i = 0; i < thumbs.length; i++) {
            var thumb = thumbs[i];
            var show = function (event) {
                event.preventDefault();
                var imgBlock = this.querySelector(fullImgContainer);
                if (imgBlock.style.display != 'block') {
                    $(fullImgContainer).hide();
                    $(imgBlock).fadeIn(500);
                } else {
                    $(imgBlock).fadeOut(500);
                }
            };
            $(thumb).bind('click', show);
        }
    };