用Response输出图片

        System.Drawing.Bitmap map = new Bitmap(Server.MapPath("2008.jpg")); 
        //调整图片的长短比 
        double dl;
        double maxlength = 400;
        if (map.Width >= map.Height)
        {
            dl = (double)(maxlength / (double)map.Width);//求比例

        }
        else
        {
            dl = (double)(maxlength / (double)map.Height);
        }
        //构建新的图片 
        System.Drawing.Bitmap newmap=new Bitmap(map,(int)(map.Width*dl),(int)(map.Height*dl)); 
        Response.Clear(); 
        //图片写入流中 
        newmap.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg); 
        //释放内存 
        map.Dispose(); 
        newmap.Dispose(); 
        Response.End();

转载于:https://www.cnblogs.com/cooolbin/archive/2008/03/01/1087190.html