1.function ShowLargeImg()
{
var url=hidImgUrl.value;
var imgWin=window.open('','img','width=50,height=50,scrollbars=yes,resizable=yes,location=no,status=no')//打开一个空白窗口，并初始化大小
imgWin.focus()//使窗口聚焦，成为当前窗口
var HTML="<html>\r\n<head>\r\n<title>picture browse</title>\r\n</head>\r\n<body leftmargin=\"0\" topmargin=\"0\">\r\n<img src=\""+url+"\" onload=\"window.resizeTo(this.width+30,this.height+35);if(screen.width>this.width && screen.height>this.height) {window.moveTo((screen.width-this.width)/2,(screen.height-this.height)/2);} else {window.moveTo(-4,-4);window.resizeTo(screen.availWidth+9,screen.availHeight+9);}\">\r\n</body>\r\n</html>"//这里是关键代码，在图片加载完后调用resizeTo()和moveTo()方法调整窗口大小和位置
var doc=imgWin.document
doc.open("text/html","replace") //指定文档的多用途网际邮件扩充协议
doc.write(HTML)//向空白窗口写入代码
doc.close()//关闭输入流，并强制发送数据显示。
}
2.
<a href="javascript:;ShowLargeImg();"><asp:Image ID="imgPic" runat="server" ToolTip="Clicking can enlarge image" alt="The picture path is wrong." /></a>
