保存图片后图片变得很大，原来32k保存后120k

[whynotwanghuilong]

怎么才能把图片变小，System.Drawing.Imaging.Encoder.Quality 说是1-100， 但我修改成那个都一样都是120k

ImageCodecInfo[] icis = ImageCodecInfo.GetImageEncoders();
ImageCodecInfo ici = null;
foreach (ImageCodecInfo i in icis)
{
if (i.MimeType == "image/jpeg" || i.MimeType == "image/bmp" || i.MimeType == "image/png" || i.MimeType == "image/gif")
{
ici = i;
}
}
EncoderParameters encoderParams = new EncoderParameters();
long[] quality = new long[1];
quality[0] = 80; //压缩比例，
EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
//EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, ((long)80));
encoderParams.Param[0] = encoderParam;
bitmap.Save(thumbnailPath, ici, encoderParams);
encoderParams.Dispose();

[liutao132]

public static byte[] ResizeImageFile(byte[] imageFile, int targetSizeW, int targetSizeH)

{

   System.Drawing.Image original = System.Drawing.Image.FromStream(new MemoryStream(imageFile));

   int targetH, targetW;

   targetW = targetSizeW;

   targetH = (int)(original.Height * ((float)targetSizeW / (float)original.Width));

   if (targetH > targetSizeH)

   {

      targetH = targetSizeH;

      targetW = (int)(original.Width * ((float)targetSizeH / (float)original.Height));

   }

   if (targetSizeW < (int)original.Width || targetSizeH < (int)original.Height)

   {

      System.Drawing.Image imgPhoto = System.Drawing.Image.FromStream(new MemoryStream(imageFile));

      // Create a new blank canvas.  The resized image will be drawn on this canvas.

      Bitmap bmPhoto = new Bitmap(targetW, targetH, PixelFormat.Format24bppRgb);

      bmPhoto.SetResolution(72, 72);

      Graphics grPhoto = Graphics.FromImage(bmPhoto);

      grPhoto.SmoothingMode = SmoothingMode.AntiAlias;

      grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;

      grPhoto.PixelOffsetMode = PixelOffsetMode.HighQuality;

      grPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, targetW, targetH), 0, 0, original.Width, original.Height, GraphicsUnit.Pixel);

      // Save out to memory and then to a file.  We dispose of all objects to make sure the files don't stay locked.

      MemoryStream mm = new MemoryStream();

      bmPhoto.Save(mm, System.Drawing.Imaging.ImageFormat.Jpeg);

      original.Dispose();

      imgPhoto.Dispose();

      bmPhoto.Dispose();

      grPhoto.Dispose();

      return mm.GetBuffer();

   }

   else

   {

      return imageFile;

   }

}

[whynotwanghuilong]

bmPhoto.Save(mm, System.Drawing.Imaging.ImageFormat.Jpeg);
这个出来的清晰度很低，原32k 出来时7k左右，清晰度太差~

[whynotwanghuilong]

求高手，急用，我怎么修改quality 1--100 我都试过了，出来的都是超大容量（120k），没反应