c#多图片上传并生成缩略图的实例代码

                 strImg += buffer.ToString();
             }
             catch
             {
                 fs.Close();
                 br.Close();

             }
             if (strImg == "255216" || strImg == "13780")//说明255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar
             {
                 result = true;
             }
             return result;
         }
     }
     #endregion

   #region 将图片生成缩略图
     /// <summary>
     /// 生成缩略图
     /// </summary>
     private void SmallImg(Stream oStream, string FileName)
     {
         using (System.Drawing.Image img = System.Drawing.Image.FromStream(oStream))
         {
             int newWidth = 100;
             int newHeight = 80;
             int oldWidth = img.Width;
             int oldHeight = img.Height;
             if (oldWidth > oldHeight)
             {
                 newHeight = (int)Math.Floor((double)oldHeight * (double)newWidth / (double)oldWidth);
             }
             else
             {
                 newWidth = (int)Math.Floor((double)oldWidth * (double)newHeight / (double)oldHeight);
             }