/*按比例生成缩略图*/
function DrawImage1(ImgD,W,H){ 
  var flag=false; 
  var image=new Image(); 
  image.src=ImgD.src; 
  if(image.width>0 && image.height>0){ 
    flag=true; 
    if(image.width/image.height>= W/H){ 
      if(image.width>W){
        ImgD.width=W; 
        ImgD.height=(image.height*H)/image.width; 
      }
	  else{ 
        ImgD.width=image.width;
        ImgD.height=image.height; 
      } 
      ImgD.alt= ""; 
    } 
    else{ 
      if(image.height>H){
        ImgD.height=H; 
        ImgD.width=(image.width*W)/image.height; 
      }
	  else{ 
        ImgD.width=image.width;
        ImgD.height=image.height; 
      } 
      ImgD.alt=""; 
    } 
  }
}




var flag=false;   //控制小图
function DrawImage(ImgD,maxwidth,maxheight){
   var image=new Image();
   image.src=ImgD.src;
   if(image.width>0 && image.height>0){
    flag=true;
    if(image.width/image.height>=maxwidth/maxheight){
     if(image.width>maxwidth){
     ImgD.width=maxwidth;
     ImgD.height=(image.height*maxwidth)/image.width;
     }else{
     ImgD.width=image.width;
     ImgD.height=image.height;
     }
     }
    else{
     if(image.height>maxheight){
     ImgD.height=maxheight;
     ImgD.width=(image.width*maxheight)/image.height;
     }else{
     ImgD.width=image.width;
     ImgD.height=image.height;
     }
     }
    }
}