function ReSizePic(ThisPic,LockWW,LockHH)
{ /*LockWW=50;LockHH=30; onload="javascript:ReSizePic(this);"*/
  ImgWW=ThisPic.width;    ImgHH=ThisPic.height; 
  if((ImgWW<=0)||(ImgHH<=0)) 
  {
        ThisPic.height=ImgHH;
        ThisPic.width=ImgWW;
  }else{
    ImgScale=ImgWW/ImgHH;   LockScale=LockWW/LockHH;
    if(ImgScale>LockScale){
      if(ImgWW>LockWW){
        ThisPic.height=LockWW/ImgScale;
        ThisPic.width=LockWW;}
    }else{
      if(ImgHH>LockHH){
        ThisPic.width=LockHH*ImgScale;
        ThisPic.height=LockHH;}
    } 
  }
}

/*µ÷ÓÃ:  
<img src="****" onload="javascript:ReSizePic(this,MaxW,MaxH);">
*/