System.Drawing and NativeAOT

final.cs

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp.Processing;
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;

namespace NativeAOTImages
{
    class Program
    {
        static void Main(string[] args)
        {
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                // Magic string which make System.Drawing.Common works.
                ComWrappers.RegisterForMarshalling(WinFormsComInterop.WinFormsComWrappers.Instance);
            }

            // System.Drawing.Common part
            int width = 128;
            int height = 128;
            var file = args[0];
            Console.WriteLine($"Loading {file}");
            using var pngStream = new FileStream(args[0], FileMode.Open, FileAccess.Read);
            using var image = new Bitmap(pngStream);
            var resized = new Bitmap(width, height);
            using var graphics = Graphics.FromImage(resized);
            graphics.CompositingQuality = CompositingQuality.HighSpeed;
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.CompositingMode = CompositingMode.SourceCopy;
            graphics.DrawImage(image, 0, 0, width, height);
            resized.Save($"resized-{file}", ImageFormat.Png);
            Console.WriteLine($"Saving resized-{file} thumbnail");

            // ImageSharp part.
            using (SixLabors.ImageSharp.Image<Rgba32> image2 = SixLabors.ImageSharp.Image.Load<Rgba32>(file))
            {
                image2.Mutate(x => x
                    .Resize(image2.Width / 2, image2.Height / 2)
                    .Grayscale());
                image2.Save($"resized-sharp-{file}"); // Automatic encoder selected based on extension.
                Console.WriteLine($"Saving resized-sharp-{file} thumbnail using ImageSharp");
            }
        }
    }

}

GdipCreateBitmapFromStream.cs

[DllImport("gdiplus.dll", ExactSpelling = true)]
internal static extern int GdipCreateBitmapFromStream(IStream stream, out IntPtr bitmap);

IgnoresAccessChecksToAttribute.cs

[assembly: global::System.Runtime.CompilerServices.IgnoresAccessChecksTo("System.Drawing.Common")]

namespace System.Runtime.CompilerServices
{
    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true, Inherited = false)]
    public class IgnoresAccessChecksToAttribute: Attribute
    {
        public IgnoresAccessChecksToAttribute(string assemblyName)
        {
            this.AssemblyName = assemblyName;
        }

        public string AssemblyName { get; }
    }
}

magic-command.cs

if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
    // Magic string which make System.Drawing.Common works.
    ComWrappers.RegisterForMarshalling(WinFormsComInterop.WinFormsComWrappers.Instance);
}

project-augmentation.csproj

<TargetFramework>net5.0-windows</TargetFramework>
<UseWindowsForms>true</UseWindowsForms>
<DisableWinExeOutputInference>true</DisableWinExeOutputInference>

project.csproj

<ProjectReference Include="..\System.Drawing.Common\System.Drawing.Common.csproj">
  <PrivateAssets>All</PrivateAssets>
  <Aliases>drawing</Aliases>
</ProjectReference>