Event.observe(window,'load',function(){

    var all_images = $$('img[class="preview"]');

    for(i=0;i<all_images.length;i++){

      all_images[i].observe('mouseover',function(n_image){ preview(Event.element(n_image),'on'); });

      all_images[i].observe('mouseout',function(n_image){ preview(Event.element(n_image),'off'); });

    }

  });



  function preview(n_image,n_switch){



    var max_size = 350;

    var img_url;

    var check;

    var new_width;

    var new_height;

    var sizes;



    if(n_switch == 'on' && ($(n_image).offsetHeight < max_size && $(n_image).offsetWidth < max_size)){



      $(n_image).setAttribute('id',$(n_image).offsetWidth+'|'+$(n_image).offsetHeight);



      check = $(n_image).offsetWidth/$(n_image).offsetHeight;

      new_width = (check < 1 ? max_size*check : max_size);

      new_height = (check < 1 ? max_size : max_size/check)



      $(n_image).setStyle({

        'width' : new_width + 'px',

        'height' : new_height + 'px',

        'z-index' : '99',

        'margin-left' : ((new_width-$(n_image).offsetWidth)/2)*(-1) + 'px',

        'margin-top' : ((new_height-$(n_image).offsetHeight)/2)*(-1) + 'px',

        'border' : '1px solid #aaa'

      });



      img_url = n_image.src.split('thumbnail_images');

      $(n_image).setAttribute('src',img_url[0] + 'popup_images' + img_url[1]);



    }

    else if(n_switch == 'off' && ($(n_image).offsetHeight >= max_size || $(n_image).offsetWidth >= max_size) && $(n_image).getAttribute('id')){



      sizes = $(n_image).getAttribute('id').split("|");



      $(n_image).setStyle({

        'width' : sizes[0] + 'px',

        'height' : sizes[1] + 'px',

        'z-index' : '1',

        'margin' : '3px',

        'border' : 'none'

      });



      img_url = n_image.src.split('popup_images');

      n_image.src = img_url[0] + 'thumbnail_images' + img_url[1];



    }



  }