function DrawImage(ImgD,iwidth,iheight){
	var image=new Image();
//	var iwidth=290; //定义允许图片宽度，当宽度大于这个值时等比例缩小
//	var iheight=230; //定义允许图片高度，当宽度大于这个值时等比例缩小
	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;
			}
			ImgD.alt=image.width+"×"+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;
			}
			ImgD.alt=image.width+"×"+image.height;
		}
	}
}