CSS实现图片等比例缩小不变形的实例代码

 <img src="../images/bg1.jpg" alt="" />
       img {
            /*等宽缩小不变形*/
            /*width: 100%;*/
            /*二选一*/
            /*等高缩小不变形*/
            height: 100%;
        }   

img {max-width:630px;myimg:expression_r(onload=function(){this.style.width=(this.offsetWidth > 630)?"630px":"auto"});}

img,a img{
border:0;
margin:0;
padding:0;
max-width:590px;
width:e­xpression(this.width>590?"590px":this.width);
max-height:590px;
height:e­xpression(this.height>590?"590px":this.height);
}

div img {
max-width:600px;
width:600px;
width:expression(document.body.clientWidth>600?”600px”:”auto”);
overflow:hidden;
}

<imgsrc="..."alt="..."onload="resizeImage(this)"/>
<script type="text/javascript">
　　functionresizeImage(obj){
　　obj.width=obj.width>50&&obj.width>obj.height?50:auto;
　　obj.height=obj.height>50?50:auto;
　　}
</script>