function init_product_gallery(thumb_width, thumb_height, big_width, big_height, change_on_click, has_loupe) {

  var preview_images = $('#product-slider-box .product-slider-preview-img');
  var size = preview_images.size();

  // Remove css selected.
  preview_images.removeClass('selected');
  // Initialize css for the current image
  $(preview_images[0]).addClass('selected');

  thumb_width_str = "width=" + thumb_width;
  thumb_height_str = "height=" + thumb_height;
  big_width_str = "width=" + big_width;
  big_height_str = "height=" + big_height;

  for (i=0; i<size; i++) {
    preview = $(preview_images[i]);
    if (change_on_click == true){
      preview.click(function (){
          set_as_big_thumb($(this), preview_images, thumb_width_str, thumb_height_str, big_width_str, big_height_str, has_loupe)
      });
    }else{
      preview.hover(function (){
          set_as_big_thumb($(this), preview_images, thumb_width_str, thumb_height_str, big_width_str, big_height_str, has_loupe)
      });
    }
  }

  if(has_loupe == true){
    $('#product-slider-big-a').loupe();
  }else{
    $('#product-slider-big-a').attr('href', '');
  }
}

function set_as_big_thumb(e, preview_images, thumb_width_str, thumb_height_str, big_width_str, big_height_str, has_loupe){
  // Remove css selected.
  preview_images.removeClass('selected');
  // Add css selected to current image
  e.addClass('selected');
  var new_src = e.attr('src');
  new_src = new_src.replace(thumb_width_str, big_width_str);
  new_src = new_src.replace(thumb_height_str, big_height_str);
  $('#product-slider-big-img').attr('src', new_src);
  // Change href
  if(has_loupe == true){
    href = new_src.replace(';thumb?', ';download');
    href = href.replace(big_width_str, '');
    href = href.replace(big_height_str, '');
    href = href.replace('&', '');
    $('#product-slider-big-a').attr('href', href);
    $('#product-slider-big-a').loupe();
  }else{
    $('#product-slider-big-a').attr('href', '');
  }
}