WPF C# split picture into small pieces and show in grid cells

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Rectangle = System.Drawing.Rectangle;
using System.IO;

namespace WpfApp288
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        string path = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
        List<List<string>> imgsList = new List<List<string>>();
        public MainWindow()
        {
            InitializeComponent();
            WindowState = WindowState.Maximized;
            SplitBigPicture();
            ShowSplitImageInGridCells();
        }

        private void ShowSplitImageInGridCells()
        {
            Grid gd = new Grid();
            gd.ShowGridLines = true;
            for (int i = 0; i < 8; i++)
            {
                RowDefinition rowDef = new RowDefinition();
                gd.RowDefinitions.Add(rowDef);
                ColumnDefinition colDef = new ColumnDefinition();
                gd.ColumnDefinitions.Add(colDef);
            }

            for (int row = 0; row < 8; row++)
            {
                var colImgsList = imgsList[row];
                for (int col = 0; col < 8; col++)
                {
                    System.Windows.Controls.Image img = new System.Windows.Controls.Image();
                    img.Stretch = Stretch.Fill;
                    Grid.SetRow(img, row);
                    Grid.SetColumn(img, col);
                    img.Source=new BitmapImage(new Uri(colImgsList[col], UriKind.RelativeOrAbsolute));
                    gd.Children.Add(img); 
                }
            }
            this.Content = gd;
        }

        private void SplitBigPicture()
        {
            string imgUrl = @"../../Images/1.jpg";
            int idx = 0;
            if (System.IO.File.Exists(imgUrl))
            {
                Bitmap bp = new Bitmap(imgUrl);
                int originalWidth = bp.Width;
                int originalHeight = bp.Height;
                int newWidth = bp.Width / 8;
                int newHeight = bp.Height / 8;
                string destDir = System.IO.Path.Combine(path, "Split8");
                if (!Directory.Exists(destDir))
                {
                    Directory.CreateDirectory(destDir);
                }
                for (int row = 0; row < 8; row++)
                {
                    List<string> colsImgsList = new List<string>();
                    for (int col = 0; col < 8; col++)
                    {
                        Bitmap newBp = new Bitmap(newWidth, newHeight);
                        using (Graphics g = Graphics.FromImage(newBp))
                        {
                            Rectangle srcRect = new System.Drawing.Rectangle(0 + col * newWidth, 0 + row * newHeight, newWidth, newHeight);
                            g.DrawImage(bp, 0, 0, srcRect, GraphicsUnit.Pixel);
                        }
                        string newFileName = System.IO.Path.Combine(destDir, $"{row}_{col}.jpg");
                        colsImgsList.Add(newFileName);
                        newBp.Save(newFileName);
                    }
                    imgsList.Add(colsImgsList);
                }
            }
        }
    }
}