MemoryCardGame C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
// second version MemoryCardGame C# assets_pic any pictures that contain unique picture
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        Button[,] tb;
        //int[] egesztomb;
        Random r;
        int lepes;
        int talalat;
        Button b1, b2;

        public Form1()
        {
            InitializeComponent();
            r = new Random();
            tb = new Button[4, 4];
            b1 = b2 = null;

        }






        private void Form1_Load(object sender, EventArgs e)
        {
            images = new Image[8];

          images[0] = resizeImage(Image.FromFile("assets_pic/1.png"), new Size(150, 150)); ;

            images[1] = resizeImage(Image.FromFile("assets_pic/2.png"), new Size(150, 150)); ;
            images[2] = resizeImage(Image.FromFile("assets_pic/3.png"), new Size(150, 150)); ;
            images[3] = resizeImage(Image.FromFile("assets_pic/4.png"), new Size(150, 150)); ;
            images[4] = resizeImage(Image.FromFile("assets_pic/5.png"), new Size(150, 150)); ;
            images[5] = resizeImage(Image.FromFile("assets_pic/6.png"), new Size(150, 150)); ;
            images[6] = resizeImage(Image.FromFile("assets_pic/7.png"), new Size(150, 150)); ;
            images[7] = resizeImage(Image.FromFile("assets_pic/8.png"), new Size(150, 150)); ;
        }

        private void bt2CloseTheGame_Click(object sender, EventArgs e)
        {
            this.Close();
        }
        private static System.Drawing.Image resizeImage(System.Drawing.Image imgToResize, Size size)
        {
            //Get the image current width
            int sourceWidth = imgToResize.Width;
            //Get the image current height
            int sourceHeight = imgToResize.Height;
            float nPercent = 0;
            float nPercentW = 0;
            float nPercentH = 0;
            //Calulate  width with new desired size
            nPercentW = ((float)size.Width / (float)sourceWidth);
            //Calculate height with new desired size
            nPercentH = ((float)size.Height / (float)sourceHeight);
            if (nPercentH < nPercentW)
                nPercent = nPercentH;
            else
                nPercent = nPercentW;
            //New Width
            int destWidth = (int)(sourceWidth * nPercent);
            //New Height
            int destHeight = (int)(sourceHeight * nPercent);
            Bitmap b = new Bitmap(destWidth, destHeight);
            Graphics g = Graphics.FromImage((System.Drawing.Image)b);
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            // Draw image with new width and height
            g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
            g.Dispose();
            return (System.Drawing.Image)b;
        }

        private void bt1NewGame_Click(object sender, EventArgs e)
        {
            if (tb[0, 0] != null)
            {
                for (int i = 0; i < 4; i++)
                {
                    for (int j = 0; j < 4; j++)
                    {
                        tb[i, j].Dispose();
                    }
                }
            }
            lepes = 0;
            label2.Text = lepes.ToString();
            talalat = 0;
            label4.Text = talalat.ToString();
            for (int i = 0; i < 4; i++)
            {
                for (int j = 0; j < 4; j++)
                {
                    tb[i, j] = new Button();
                    tb[i, j].Parent = pmain;
                    tb[i, j].Width = 150;
                    tb[i, j].Height = 150;
                    tb[i, j].Left = j * 150;
                    tb[i, j].Top = i * 150;
                    tb[i, j].Tag = 0;
                    tb[i, j].BackColor = Color.DarkGray;
                    tb[i, j].FlatStyle = FlatStyle.Flat;
                    tb[i, j].Click += Klikk;
                }
            }
            for (int i = 1; i <= 2; i++)
            {
                for (int j = 1; j <= 8; j++)
                {
                    int x, y;
                    do
                    {
                        x = r.Next(0, 4);
                        y = r.Next(0, 4);
                    } while ((int)tb[x, y].Tag != 0);
                    tb[x, y].Tag = j;
                }
            }
        }
        Image[] images = null;
        private async void Klikk(object sender, EventArgs e)
        {
            Button b = sender as Button;
            b.Text = "";
            b.Enabled = false;




            b.Text = ((int)b.Tag-1).ToString();


            label2.Text = (++lepes).ToString();
            if (b1 == null)
            {
                b1 = b;
                b1.BackgroundImage = images[(int)b.Tag - 1];
            }
            else if (b2 == null)
            {
                b2 = b;
                b2.BackgroundImage = images[(int)b.Tag - 1];

                if (b1.Text == b2.Text)
                {
                    label4.Text = (++talalat).ToString();
                    //   b1.BackColor = Color.LightBlue;
                    //  b2.BackColor = Color.LightBlue;

                    b1.BackgroundImage = images[(int)b.Tag - 1];
                    b2.BackgroundImage = images[(int)b.Tag - 1];
                    if (talalat == 8)
                    {
                        MessageBox.Show("Gratulálok! " + lepes.ToString() + " lépésből megoldotta!");
                    }
                }
                else
                {
                    //  Application.DoEvents();
                    await Task.Delay(500);
                    b1.Text = "";
                    b2.Text = "";
                    b1.Enabled = true;
                    b2.Enabled = true;
                    b = null;
                    b1.BackColor = Color.DarkGray;
                    b2.BackColor = Color.DarkGray;
                    b1.BackgroundImage = null;
                    b2.BackgroundImage = null;
                }
                b1 = b2 = null;

                foreach (Button ReInit in tb)
                {

                    ReInit.Text = "";
                    if (ReInit.BackgroundImage == null)
                    {
                        ReInit.Enabled = true;
                    }
                }

            }
        }

    }
}