C# Bitmap in array und Anzeigen

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.IO;

using System.Windows;

using System.Drawing.Imaging;

using System.Drawing;

using System.Runtime.InteropServices;

namespace myProgram

{

    class rendering

    {

        // nimmt mein Objekt pixarray und macht daraus einen bmp stream

        internal static Image render(pixarray pixels)

        {

            // neues bitmap

            var b = new Bitmap(pixels.getsizeX(), pixels.getsizeY(), PixelFormat.Format8bppIndexed);

            // erstelle farbpalette

            ColorPalette ncp = b.Palette;

            for (int i = 0; i < 256; i++)

                ncp.Entries[i] = Color.FromArgb(255, i, i, i);

            b.Palette = ncp;

            // kopierter code, macht auch irgendwas

            var BoundsRect = new Rectangle(0, 0, pixels.getsizeX(), pixels.getsizeY());

            BitmapData bmpData = b.LockBits(BoundsRect,

                                            ImageLockMode.WriteOnly,

                                            b.PixelFormat);

            IntPtr ptr = bmpData.Scan0;

            // sortiert 2D-Array in 1D um

            int bytes = bmpData.Stride * b.Height;

            var rgbValues = new byte[bytes];

            for (int y = 0; y < pixels.getsizeY(); ++y)

            {

                for (int x = 0; x < pixels.getsizeX(); ++x)

                {

                    rgbValues[y * pixels.getsizeX() + x] = (byte)(255-pixels.getpix(x, y)*255);

                }

            }

            Marshal.Copy(rgbValues, 0, ptr, bytes);

            b.UnlockBits(bmpData);

            return b;

        }

    }

}