How to convert a JPG image to an 8-bit PNG image and save in C#?

Question

I have captured a JPG image using a Webcam in C# and have stored it in a folder.

Now I want to convert it to an 8-bit PNG image.

I checked all over internet and Stack Overflow, but none of the proposed solutions work for me.

Here is what I am currently using:

Bitmap img = new Bitmap(imgPath);
Bitmap img8 = new Bitmap(imgW, imgH, PixelFormat.Format16bppRgb565);

for (int I = 0; I <= img.Width - 1; I++)
    for (int J = 0; J <= img.Height - 1; J++) 
        img8.SetPixel(I, J, img.GetPixel(I, J));

However, this throws the following exception:

SetPixel is not allowed for indexed pixel images.

Answer 1

you have to perform some programming by your self. you can find an example logic and code here http://codingresolved.com/discussion/2185/save-png-image-as-8bit-format-in-c

Answer 2

You could try to use ImageMagick, it contains a utility to convert files. You can use either the command line interface or a .Net connector like magick.Net.

Using the command line, you could launch a process that runs the following command:

convert [yourfile.jpg] -depth 8 [yourfile.png]

That's probably overkill, but that's the only option I know to work on images.

Answer 3

No i cant use Gif. BUt can use TIFF.

Image orgBmp = Image.FromFile(@"fname.jpg");

var tiffEncoder = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders()
                  .First(e => e.FormatDescription == "TIFF");


EncoderParameters parameters = new EncoderParameters(1);
parameters.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.ColorDepth, (long)ColorDepth.Depth8Bit);

orgBmp.Save(@"fname.tif", tiffEncoder, parameters);