MainPage.xaml.cs

private readonly List<Image> _cells = new List<Image>();

private void PrepareGrid()
{
    GameCanvas.Children.Clear();

    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;
            GameCanvas.Children.Add(cell);
        }
    }
}

private Image GetCell(int row, int column)
{
    var index = row * _gameState.Size + column;
    return GetCell(index);
}

private Image GetCell(int order)
{
    while (_cells.Count <= order)
    {
        _cells.Add(CreateCell());
    }

    return _cells[order];
}

private Image CreateCell() => new Image();