MainPage.xaml.cs

private BitmapImage _aliveBitmap = new BitmapImage(new Uri($"ms-appx:///Assets/Classic_alive.png"));
private BitmapImage _deadBitmap = new BitmapImage(new Uri($"ms-appx:///Assets/Classic_dead.png"));

private void RedrawBoard()
{
    for (var row = 0; row < _gameState.Size; row++)
    {
        for (var column = 0; column < _gameState.Size; column++)
        {
            var cell = GetCell(row, column);
            cell.Source = _gameState.Cells[row, column] == CellState.Alive ?
                _aliveBitmap : _deadBitmap;
        }
    }
}