function DrawImage(ImgD, iwidth){
    var image=new Image();

    var iheight = 99999; //默认高
    image.src=ImgD.src;
    if(image.width>0 && image.height>0){
        if(image.width/image.height>= iwidth/iheight){
            if(image.width>iwidth){
                ImgD.width=iwidth;
                ImgD.height=(image.height*iwidth)/image.width;
            }else{
                ImgD.width=image.width;
                ImgD.height=image.height;
            }
        }else{
            if(image.height>iheight){
                ImgD.height=iheight;
                ImgD.width=(image.width*iheight)/image.height;
            }else{
                ImgD.width=image.width;
                ImgD.height=image.height;
            }
        }
    }
}