LoadMauiImageAsStream.cs

using Microsoft.Maui.Platform;

namespace MauiApp84;

public static class ImageLoading
{
#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
	public static async Task<Stream> LoadImageStreamAsync(string file, CancellationToken cancellationToken)
#pragma warning restore CS1998 // Async method lacks 'await' operators and will run synchronously
	{
		if (Path.IsPathRooted(file) && File.Exists(file))
			return File.OpenRead(file);

#if ANDROID
		var context = Android.App.Application.Context;
		var resources = context.Resources;

		var resourceId = context.GetDrawableId(file);
		if (resourceId > 0)
		{
			var imageUri = new Android.Net.Uri.Builder()
				.Scheme(Android.Content.ContentResolver.SchemeAndroidResource)
				.Authority(resources.GetResourcePackageName(resourceId))
				.AppendPath(resources.GetResourceTypeName(resourceId))
				.AppendPath(resources.GetResourceEntryName(resourceId))
				.Build();

			var stream = context.ContentResolver.OpenInputStream(imageUri);
			if (stream is not null)
				return stream;
		}
#elif WINDOWS
		try
		{
			var sf = await Windows.Storage.StorageFile.GetFileFromPathAsync(file);
			if (sf is not null)
			{
				var stream = await sf.OpenStreamForReadAsync();
				if (stream is not null)
					return stream;
			}
		}
		catch
		{
		}

		if (AppInfo.PackagingModel == AppPackagingModel.Packaged)
		{
			var uri = new Uri("ms-appx:///" + file);
			var sf = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(uri);
			var stream = await sf.OpenStreamForReadAsync();
			if (stream is not null)
				return stream;
		}
		else
		{
			var root = AppContext.BaseDirectory;
			file = Path.Combine(root, file);
			if (File.Exists(file))
				return File.OpenRead(file);
		}
#elif IOS || MACCATALYST
		var root = Foundation.NSBundle.MainBundle.BundlePath;
#if MACCATALYST || MACOS
		root = Path.Combine(root, "Contents", "Resources");
#endif
		file = Path.Combine(root, file);
		if (File.Exists(file))
			return File.OpenRead(file);
#endif

		return null;
	}
}

This doesn't seem to work on Windows .NET 8

Edit: Figured it out: var sf = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///" + file));