てくなんず

tekunyans.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        Image img = Image.FromFile("imgres.jpg");
        List<Point> points = new List<Point>();

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Point p = new Point();
            Random rnd = new Random();
            p.X = rnd.Next(pictureBox1.Width);
            p.Y = rnd.Next(pictureBox1.Height);

            points.Add(p);

            pictureBox1.Refresh();
        }

        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            foreach (Point p in points) {
                e.Graphics.DrawImage(img, p);
            }
        }
    }
}