$(function(){

  var image_src = $('#home_cover')
    .attr('src')
    .replace(/\.jpg/, '_pop_up.jpg');

  $('body').append('\
    <div id="home_cover_large" class="overlay">\
      <img src="' + image_src + '" width="100%" />\
    </div>\
  ');

  $('#home_cover').overlay({ 
    effect:       'apple',
    closeOnClick: true
  });

});