void image()
{
    for (int i = 1; i <= 25; i++)
    {
        Image image = new Image();
        centerGrid.Children.Add(image);
        image.Stretch = Stretch.Fill;
        image.Source = new BitmapImage(new Uri("Image/back.png", UriKind.Relative));
    }
}

void image()
{
  for (int i = 1; i <= 5; ++i)
  {
    for (int j = 0; j < 5; ++j)
    {
      Image image = new Image();

      image.SetValue(Grid.RowProperty, i);
      image.SetValue(Grid.ColumnProperty, j);

      grid.Children.Add(image);
      image.Stretch = Stretch.Fill;
      image.Source = new BitmapImage(new Uri("Images/1.png", UriKind.Relative));
    }
  }
}

void image()
{
  for (int i = 1; i <= 25; ++i)
  {
    Image image = new Image();

    // + обработка 0 значения..
    image.SetValue(Grid.RowProperty, i % 5);
    image.SetValue(Grid.ColumnProperty, i / 5);

    grid.Children.Add(image);
    image.Stretch = Stretch.Fill;
    image.Source = new BitmapImage(new Uri("Images/1.png", UriKind.Relative));
  }
}

Grid.SetRow(image, i);
Grid.SetColumn(image, j);