var source = args[0];

if (!File.Exists(source))
  throw new FileNotFoundException($"Input image not found", source);

var sourceImage = CvInvoke.Imread(source);
var mat = new Mat();

CvInvoke
  .ResizeForFrame(sourceImage, mat, new Size(64, 64), Inter.Lanczos4, true);

var image = mat.ToImage<Bgr, byte>();

ExcelPackage.LicenseContext = LicenseContext.NonCommercial;

using var package = new ExcelPackage(
  new FileInfo(source.Replace(Path.GetExtension(source), ".xlsx"))
);

var worksheet = package.Workbook.Worksheets["Pixcel"]
                ?? package.Workbook.Worksheets.Add("Pixcel");

for (var y = 1; y <= image.Height; y++)
{
  worksheet.Row(y).Height = 27.5;

  for (var x = 1; x <= image.Width; x++)
  {
    worksheet.Column(x).Width = 5;
    worksheet.Cells[y, x].Style.Fill.PatternType = ExcelFillStyle.Solid;
    worksheet.Cells[y, x].Style.Fill.BackgroundColor.SetColor(
      0,
      image.Data[y-1, x-1, 2],
      image.Data[y-1, x-1, 1],
      image.Data[y-1, x-1, 0]
    );
  }
}

package.Save();