图片格式转换并按指定调色板修改颜色深铳

public static void SaveImage(string fileName, int quality)

 {

     //读取画像文件

     Bitmap  bmp= new Bitmap(fileName);

 

     // EncoderParameter对象只能容纳1个

     // EncoderParameters类的新instance初始化

     //在这里只是指定质量值，所以只需要1个

     System.Drawing.Imaging.EncoderParameters eps =

         new System.Drawing.Imaging.EncoderParameters(1);

     //指定质量

     System.Drawing.Imaging.EncoderParameter ep =

         new System.Drawing.Imaging.EncoderParameter(

         System.Drawing.Imaging.Encoder.Quality, quality);

     eps.Param[0] = ep;

 

     //取得ImageEncoder相关的信息

     System.Drawing.Imaging.ImageCodecInfo ici;

     ici = GetEncoderInfo("image/jpeg");

 

     //取得新文件的扩展名

     string ext = ici.FilenameExtension.Split(';')[0];

     ext = System.IO.Path.GetExtension(ext).ToLower();

 

     //定保存文件的名称(改变扩展名)

     string saveName= System.IO.Path.ChangeExtension(fileName, ext);

 

     //保存

     bmp.Save(saveName, ici, eps);

 }

 

 private static System.Drawing.Imaging.ImageCodecInfo

     GetEncoderInfo(string mineType)

 {

     //取得所有向GDI+被装入的ImageEncode相关信息

     System.Drawing.Imaging.ImageCodecInfo [] encs=

         System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders();

     //如果检测到被指定的MimeType，返回

     foreach (System.Drawing.Imaging.ImageCodecInfo enc in encs)

         if (enc.MimeType == mineType)

             return enc;

     return null;

 }