怎么编写语句挑出9的倍数的图片，求帮助

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        Image d;
        public Form1()
        {
            InitializeComponent();
        }        private void Form1_Load(object sender, EventArgs e)
        {
            int x = 10;
            int y = 0;
           
            for (int i = 0; i < 100; i++)
            {
                Label lbl = new Label();
                lbl.Text = string.Format("{0}", i + 1);
                lbl.Font = new Font("宋体", 10);
                lbl.Size = new Size(50, 30);
                if (i % 16 == 0)
                {
                    x = 10;
                    y += 90;
                }
                lbl.Location = new Point(x, y);                x += 80;
                this.Controls.Add(lbl);
            }
            Random r = new Random(); int j = 10; int k = -60; 
            for (int i = 0; i < 100; i++)
            {
                PictureBox p = new PictureBox();
              
            
                p.Image = System.Drawing.Bitmap.FromFile(@"icon\" + r.Next(1, 40) + ".bmp");                p.Width = 50;
                p.Height = 50;                if (i % 16 == 0)
                {
                    j = 10;
                    k += 90;
                }                p.Location = new Point(j, k);                j += 80;
                this.Controls.Add(p);
}
            Button b = new Button();
            b.Text = "重试";
            b.Top = 600;
            b.Left = 450;
            b.Width = 100;
            b.Height = 20;
            this.Controls.Add(b);
            Button b1 = new Button();
            b1.Text = "读心";
            b1.Top = 600;
            b1.Left = 850;
            b1.Width = 100;
            b1.Height = 20;
            this.Controls.Add(b1);
            PictureBox p1 = new PictureBox();
            p1.Image  = d;
            p1.Top = 600;
            p1.Left = 1000;
            p1.Width = 100;
            p1.Height = 100;
         
            this.Controls.Add(b1);
            }
        }
    }