Image.save - the parameter is invalid.

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C#

image-processing

I'm starting with a stream that represents an image, and drawing it onto a larger image. To do this, I wrote an extension method for MemoryStreams. When I try to save the image into a new stream, the code is throwing "Parameter is not valid" exception.

Facts:
- The stream on which I'm calling the method is NOT null, and contains data.
- When I get to the statement in question, the new image is not null, and the encoder appears to be correct.
- The recieving MemoryStream object is NOT null (indeed, that would have caused a completely different exception).

I have no clue as to why I'm getting this exception.

As you can see, I'm making use of using statements, but nothing is out of scope when I get to the statement that is throwing the exception, and the exception does not indicate WHICH parameter is invalid.

Note - the GetEncoder method was written to black-box and cleanup the methods that needed to use that code. As stated above, the encoder appears to be valid.

public static MemoryStream AddMatting(this MemoryStream stream, Size size, Color color)
{
    MemoryStream newStream = new MemoryStream();
    using (Image image = Bitmap.FromStream(stream))
    {
        using (Bitmap matting = new Bitmap(size.Width, size.Height, image.PixelFormat))
        {
            using (Graphics g = Graphics.FromImage(matting))
            {
                int x = (int)((matting.Width-image.Width)*0.5);
                int y = (int)((matting.Height-image.Height)*0.5);
                g.Clear(color);
                g.DrawImage(image, x, y);
                ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg);
                using (EncoderParameters encParams = new EncoderParameters(1))
                {
                    encParams.Param[0] = new EncoderParameter(Encoder.Quality, 100);
                    try
                    {
                        matting.Save(newStream, jpgEncoder, encParams);
                    }
                    catch (Exception ex)
                    {
                        if (ex != null) {}
                    }
                }
            }
        }
    }
    return newStream;
}

What I have tried:

0) I added true,true to the method call to FromStream, thinking maybe some how the stream was invalid, but that did not trigger an ArgumentInvalid exception, so the stream itself is valid).

1) I tried reducing the method to its simplest form (which takes the incoming stream, makes it an image, and then saves it right back to a new stream), and still get the exception:

public static MemoryStream AddMatting(this MemoryStream stream, Size size, Color color)
{
    MemoryStream newStream = new MemoryStream();
    using (var image = Bitmap.FromStream(stream))
    {
        ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg);
        using (EncoderParameters encoderParameters = new EncoderParameters(1))
        {
            encoderParameters.Param[0] = new EncoderParameter(Encoder.Quality, 100);
            try
            {
                image.Save(newStream, jpgEncoder, encoderParameters);
            }
            catch (Exception ex)
            {
                if (ex != null) {}
            }
        }
    }
    return newStream;
}