本文實例主要展示了.Net實現上傳圖片按比例自動縮小或放大的方法，是非常實用的功能。之用。具體方法如下：

//// <summary>/// 按比例縮小圖片，自動計算寬度/// </summary>/// <param name="strOldPic">源圖文件名(包括路徑)</param>/// <param name="strNewPic">縮小后保存為文件名(包括路徑)</param>/// <param name="intHeight">縮小至高度</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>/// 縮小圖片/// </summary>/// <param name="strOldPic">源圖文件名(包括路徑)</param>/// <param name="strNewPic">縮小后保存為文件名(包括路徑)</param>/// <param name="intWidth">縮小至寬度</param>/// <param name="intHeight">縮小至高度</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;  }}

希望本文所述實例對大家的asp.net程序設計有一定的借鑒價值。