Bitmap from Stream: Bug?

Question

I have a pretty strange Error. I need to scale down images, scale down the quality and convert to JPEG. This all works when I save the File on disk, but it doesn\'t work whe

Answer 1

The following code works for me:

var bitmap = new Bitmap(@"c:\Dokumente und Einstellungen\daniel.hilgarth\Desktop\Unbenannt.bmp");

ImageCodecInfo jpgEncoder = ImageCodecInfo.GetImageEncoders().Single(x => x.FormatDescription == "JPEG");
Encoder encoder2 = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters parameters = new System.Drawing.Imaging.EncoderParameters( 1 );
EncoderParameter parameter = new EncoderParameter( encoder2, 50L );
parameters.Param[0] = parameter;

System.IO.Stream stream = new MemoryStream();
bitmap.Save( stream, jpgEncoder, parameters );
bitmap.Save(@"C:\Temp\TestJPEG.jpg", jpgEncoder, parameters);

var bytes = ((MemoryStream)stream).ToArray();
System.IO.Stream inputStream = new MemoryStream(bytes);
Bitmap fromDisk = new Bitmap(@"C:\Temp\TestJPEG.jpg");
Bitmap fromStream = new Bitmap(inputStream);

There are a few differences to your code. Which one causes your problem is up to you to find out, I guess:

• I used 50L as qualityLevel. When using 1, 2, 50 or 100, I was getting an ArgumentException "Parameter is not valid". As I don't know the type or value of your qualityLevel variable that can very well be the problem.
• I replaced your GetEncoder method. I don't know what your method does exactly, so it could be the problem, but I doubt it.