title: backgroung image of the body disappears after changing tab on firefox
body: <p>i have a site with a backgroung image with 1,32mb, that's located in css of the body, the problem is when i change tab in firefox and back again on my site the background disappears, and displays a white background... someone knows what's happing ?</p>
  
  <p>//html</p>
  
  <pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head&gt;
  &lt;title&gt;Cacilda Tour&lt;/title&gt;
  &lt;link rel="StyleSheet" type="text/css" href="css/style.css" /&gt;
  &lt;script language="JavaScript" type="text/JavaScript"&gt;
  
  &lt;!-- começo do codigo random imagens
  var mypics=['toppo1.png','toppo2.png','toppo3.png'];
  onload=function(){
      var oTd = document.getElementById('cel');
      var pic= 'topo/'+mypics[Math.floor(Math.random()*mypics.length)];
      oTd.style.backgroundImage='url('+pic+')';
  }
  //  fim do codigo de imagens --&gt;
  &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;div class="principal"&gt;
      &lt;div class="cabecalho"&gt;
  
      &lt;img id="cel" src="images/topo_transp.gif" border="0" &gt;
  
      &lt;/div&gt;
      &lt;div class="menu"&gt;
  
      &lt;/div&gt;
      &lt;div class="conteudo"&gt;
          &lt;div class="centroesq"&gt;
              &lt;div class="titcentroesq"&gt;
              &lt;p&gt;Pacotes&lt;/p&gt;
              &lt;/div&gt;
          &lt;/div&gt;
          &lt;div class="centrodir"&gt;
              &lt;div class="titcentrodir"&gt;
              &lt;p&gt;Corporativo&lt;/p&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
      &lt;div class="rodape"&gt;
  
      &lt;/div&gt;
  
  
    &lt;/div&gt;
  &lt;/body&gt;
  
  &lt;/html&gt;
  </code></pre>
  
  <p>//css</p>
  
  <pre><code>body{
  background-image: url(../imagens/fundo.jpg);
  background-repeat:no-repeat;
  height:1065px;
  }
  .principal{
  width:980px;
  margin: 0 auto;
  }
  .cabecalho{
  float:left;
  width:100%;
  }
  .cabecalho img {
  width:100%;
  background-repeat:no-repeat;
  width:980px; 
  height:200px;
  }
  .menu{
  float:left;
  width:100%;
  height:40px;
  background-image: url(../imagens/fundomenu.png);
  margin-top:8px;
  -webkit-border-radius: 6px;
  -moz-border-radius: 6px;
  border-radius: 6px;
  }
  .conteudo{
  float:left;
  width:100%;
  height:700px;
  background-image: url(../imagens/fundomenu.png);
  margin-top:8px;
  -webkit-border-radius: 6px;
  -moz-border-radius: 6px;
  border-radius: 6px;
  }
  .centroesq{
  float:left;
  width:488px;
  height:300px;
  border-right:1px dotted #c0c0c0;
  margin-top:8px;
  }
  .titcentroesq{
  float:left;
  width:460px;
  height:32px;
  
  margin-left:10px;
  background-image: url(../imagens/fundotitulo.png);
  -webkit-border-radius: 6px;
  -moz-border-radius: 6px;
  border-radius: 6px;
  line-height:2px;
  color:#10468c;
  font-family:arial;
  font-size:105%;
  font-weight:bold;
  text-align:left;
  padding-left:10px;
  border:1px solid #fbca18;
  }
  .centrodir{
  float:left;
  width:490px;
  height:300px;
  margin-top:8px;
  }
  .titcentrodir{
  float:left;
  width:460px;
  height:32px;
  
  margin-left:10px;
  background-image: url(../imagens/fundotitulo2.png);
  -webkit-border-radius: 6px;
  -moz-border-radius: 6px;
  border-radius: 6px;
  line-height:2px;
  color:#ffffff;
  font-family:arial;
  font-size:105%;
  font-weight:bold;
  text-align:left;
  padding-left:10px;
  border:1px solid #2b4688;
  }
  .rodape{
  float:left;
  width:100%;
  height:95px;
  background-image: url(../imagens/fundomenu.png);
  margin-top:8px;
  -webkit-border-radius: 6px;
  -moz-border-radius: 6px;
  border-radius: 6px;
  
  }
  </code></pre>