Compressing a jpg file

[GazzaJ]

I am trying to compress a jpg file in the same manner that you would set the quality factor in an image processing package e.g. Open image1.jpg Set quality factor to 50 Save as image2.jpg This is to reduce the size of the jpg files in my application. Does anyone know if there are .NET libraries for this or any good commercial toolkits.

[Russell Jones]

System.Drawing.Imaging.EncoderParameters encParams = new System.Drawing.Imaging.EncoderParameters(); encParams.Param[0] = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, Quality); MemoryStream ms = new MemoryStream(); _reformattedImage.Save(ms, System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders()[1], encParams); _reformattedImage = Image.FromStream(ms); That's raw code straight out of an app i've got infront of me it's got the quality methods you'll need though. Quality is the parameter from 1 to 100 that sets the quality level Things like Bitmap should have load and save methods on them (you can load jpegs into bitmap objects). HTH Russ

[GazzaJ]

Thanks Russell. For completeness my final solution was: // Method to get the apprpriate encoder private ImageCodecInfo GetEncoderInfo(String mimeType) { int j; ImageCodecInfo[] encoders; encoders = ImageCodecInfo.GetImageEncoders(); for(j = 0; j < encoders.Length; ++j) { if(encoders[j].MimeType == mimeType) return encoders[j]; } return null; } // Compress file code Image image = Image.FromFile(sourceFile); string mimeType = "image/jpeg"; ImageCodecInfo codecInfo = GetEncoderInfo(mimeType); if (codecInfo == null) raise error; // Set the quality (must be a long) Encoder qualityEncoder = Encoder.Quality; EncoderParameter ratio = new EncoderParameter(qualityEncoder, 40L); EncoderParameters encoderParams = new EncoderParameters(1); encoderParams.Param[0] = ratio; image.Save(destFile, codecInfo, encoderParams); image.Dispose();