<img src="http://avatar.profile.csdn.net/0/0/0/2_natici.jpg" alt="正常图片">
<img src="http://avatar.profile.csdn.net/0/0/0/2_natici.jpg"  data="http://img4.mypsd.com.cn/20110726/mypsd_63257_201107261606130003b.jpg" alt="正常加载data图片">
<img src="http://avatar.profile.csdn.net/0/0/0/2_natici.jpg"  data="http://www.error.com/xxxx.gif" alt="出错，将加载err_url图片">

<script type="text/javascript">
var err_url="http://c.csdn.net/bbs/t/5/i/pic_logo.gif"; //定义出错后显示的图片
var img=document.getElementsByTagName("img");
    for(var i=0;i<img.length;i++){
        var att=img[i].getAttribute("data");
        if(att!=""&&att!=null){
            //没有定义data属性的图片我们不检查
            (function(a,b){
                var pic = new Image();
                pic.src = b;
                pic.onload = function () {
                    pic.onload = null;
                    img[a].src=b;
                };
                pic.onerror=function(){
                    pic.onerror = null;
                    img[a].src=err_url;
                }
            })(i,att)
        }
    }
</script>

------解决方案--------------------
HTML code
<meta charset="utf-8"/>
URL: <input id="url" type="text" />
<input type="button" value="URL" onclick="loadPic()"/><br/>
<img  id="pic1" src="" style="display:none;"/>
<script>
var LOADING_URL = 'http://t2.baidu.com/it/u=409863868,1781147496&fm=11&gp=0.jpg';
var ERROR_URL = 'http://img10.3lian.com/c1/ps/32/30/14533113.jpg';

function $(id){
  return document.getElementById(id);
}

function getPicLoader(){
  if(window.__loader){
    return window.__loader;
  }
  
  var img = new Image();
  window.__loader = img;
  return img;
}

function loadPic(){
  var loader = getPicLoader();
  var url = $('url').value;
  var showPic = $('pic1');
  
  showPic.src = LOADING_URL;
  showPic.style.display = '';
  
  loader.onload = function(){
    showPic.src = this.src;
  };
  
  loader.onerror = function(){
    showPic.src = ERROR_URL;
  };
  
  loader.src = url;
}
</script>