var thumbGallery = new Class({

  Implements: [Options, Events],
  options: {
    galleryElement: ''
  },

  initialize: function(options){

    this.setOptions(options);

    galleryElement = this.options.galleryElement;

    var thumbnails = galleryElement.getElements('.thumbs a');
    thumbnails.addEvent('click', function(el){
      el.stop();
    });
    
    thumbnails.addEvent('mouseenter', function(el){
      this.getParent('div').getParent('div').getFirst('img').setProperty('src', this.getProperty('href'));
    });

  }

});