var selected = eval(0);
var max=eval(0);
var imgs = new Array();

function cl_img(num) {
    num = eval(num);
    var old_thm = document.getElementById('t_'+selected);
    var new_thm = document.getElementById('t_'+num);
    var big_img = document.getElementById('main_image');
    old_thm.src = 'image.jpg';
    new_thm.src = 'image_s.jpg';
    selected = num;
    big_img.src = imgs[num].src;
}

function next_img() {
    var next = (selected+1) % (max+1);
    var old_thm = document.getElementById('t_'+selected);
    var new_thm = document.getElementById('t_'+next);
    var big_img = document.getElementById('main_image');
    old_thm.src = 'image.jpg';
    new_thm.src = 'image_s.jpg';
    selected = next;
    big_img.src = imgs[next].src;
}

function on_img(num) {
    num = eval(num);
    if (num != selected) {
        var thm = document.getElementById('t_'+num);
        thm.src = 'image_u.jpg';
    }
}

function off_img(num) {
    num = eval(num);
    if (num != selected) {
        var thm = document.getElementById('t_'+num);
        thm.src = 'image.jpg';
    }
}

function preload_image(num, img) {
    num = eval(num);
    imgs[num] = new Image();
    imgs[num].src = img;
    var thm = document.getElementById('t_'+num);
    if (num == selected) {
        thm.src = 'image_s.jpg';
    } else {
        thm.src = 'image.jpg';
    }
    if (num > max) {
        max = num;
    }
}