.Net实现上传图片按比例自动缩小或放大的方法

//// <summary>/// 按比例缩小图片，自动计算宽度/// </summary>/// <param name="strOldPic">源图文件名(包括路径)</param>/// <param name="strNewPic">缩小后保存为文件名(包括路径)</param>/// <param name="intHeight">缩小至高度</param>public void SmallPicWidth(string strOldPic, string strNewPic, int intHeight){  System.Drawing.Bitmap objPic, objNewPic;  try  { objPic = new System.Drawing.Bitmap(strOldPic); int intWidth = (intHeight / objPic.Height) * objPic.Width; objNewPic = new System.Drawing.Bitmap(objPic, intWidth, intHeight); objNewPic.Save(strNewPic);  }  catch (Exception exp) { throw exp; }  finally  { objPic = null; objNewPic = null;  }}/**//// <summary>/// 缩小图片/// </summary>/// <param name="strOldPic">源图文件名(包括路径)</param>/// <param name="strNewPic">缩小后保存为文件名(包括路径)</param>/// <param name="intWidth">缩小至宽度</param>/// <param name="intHeight">缩小至高度</param>public void SmallPic(string strOldPic, string strNewPic, int intWidth, int intHeight){  System.Drawing.Bitmap objPic, objNewPic;  try  { objPic = new System.Drawing.Bitmap(strOldPic); objNewPic = new System.Drawing.Bitmap(objPic, intWidth, intHeight); objNewPic.Save(strNewPic);  }  catch (Exception exp) { throw exp; }  finally  { objPic = null; objNewPic = null;  }}