var flag=false;
function DrawImage(ImgD,ImgWidth,ImgHeight){
	var image=new Image();
	var FitWidth=ImgWidth;//图片的最大宽，超过这个值就会自动缩小
	var FitHeight=ImgHeight;//按比例缩小
	image.src=ImgD.src;
	if(image.width>0 && image.height>0){
		flag=true;
		if(image.width/image.height>= FitWidth/FitHeight){
			if(image.width>FitWidth){
				ImgD.width=FitWidth;
				ImgD.height=(image.height*FitWidth)/image.width;
			}else{
				ImgD.width=image.width;
				ImgD.height=image.height;
			}
			ImgD.alt="";
		}
		else{
			if(image.height>FitHeight){
				ImgD.height=FitHeight;
				ImgD.width=(image.width*FitHeight)/image.height;
			}else{
				ImgD.width=image.width;
				ImgD.height=image.height;
			}
			ImgD.alt="";
		}
	}
}