Adds a (white) background to png images and export them to jpeg.

AddBackground.cs

using SkiaSharp;

namespace AGXSpriteProcessor
{
    // Loads all images in a directory, adds a white background, and saves them to a new directory as .jpeg
    public static class AddBackground
    {
        private const string InputDirectory = @"C:\Users\Alde\Desktop\Wik";
        private const string OutputDirectory = @"C:\Users\Alde\Desktop\Wik\Output";

        public static void AddBackgroundToImages()
        {
            var files = Directory.GetFiles(InputDirectory, "*.png");

            // Create output directory if it doesn't exist
            if (!Directory.Exists(OutputDirectory))
                Directory.CreateDirectory(OutputDirectory);

            // Use parallel for faster processing
            Parallel.ForEach(files, file =>
            {
                using var inputStream = File.OpenRead(file);
                using var bitmap = SKBitmap.Decode(inputStream);

                // Create a new bitmap with a white background
                var imageWithBackground = new SKBitmap(bitmap.Width, bitmap.Height);
                using (var canvas = new SKCanvas(imageWithBackground))
                {
                    canvas.Clear(SKColors.White);
                    canvas.DrawBitmap(bitmap, 0, 0);
                }

                // Save the new image as a .jpeg in the output directory
                var outputFilePath = Path.Combine(OutputDirectory, $"{Path.GetFileNameWithoutExtension(file)}.jpeg");
                using (var outputStream = File.OpenWrite(outputFilePath))
                {
                    Console.WriteLine($"Saving {outputFilePath}");
                    imageWithBackground.Encode(outputStream, SKEncodedImageFormat.Jpeg, 100);
                }
            });
        }
    }
}