function charlie_populate_links() {
    $("a", ".popupNav").click(function() {
        charlie_open_popup($(this).html());
    });
}

function charlie_open_popup(number) {
    var src = $('#mainImage').attr('src');
    var directory = /(.*)_/.exec(src);
    var format = /_01.(.*)/.exec(src);
    var popupNav = $('.popupNav').html();

    $('#popupContainer').removeClass('hidden');
    //$('img','#popupImage').attr('src', directory[1] + '_' + number + '.' + format[1]);
    $('img','#popupImage').remove();
    $('#popupImage').append("<img src='" + directory[1] + "_" + number + "." + format[1] + "'/>");
    if ($(".popupNav").length < 2) {
        $('#popup').append('<ul class="popupNav">' + popupNav + '</ul>');
        charlie_populate_links();
    };
}

$(document).ready(function() {
    charlie_populate_links();
});