C#

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;
using System.IO;


namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {

        Dictionary<string, string> ImageList = new Dictionary<string, string>();
        public Form1()
        {
            InitializeComponent();
            SetStyle(ControlStyles.ResizeRedraw, true);
        }
        private void button3_Click(object sender, EventArgs e)
        {
            if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
            {
                DirectoryInfo FileDirectory = new DirectoryInfo(folderBrowserDialog1.SelectedPath);
                //FileInfo[] FilesFromDirectory = FileDirectory.GetFiles();
                FileInfo[] FileJpg = FileDirectory.GetFiles("*.jpg");
                FileInfo[] FileGif = FileDirectory.GetFiles("*.gif");
                FileInfo[] FileBmp = FileDirectory.GetFiles("*.bmp");
                FileInfo[] FileTif = FileDirectory.GetFiles("*.tif");
                FileInfo[] FilePng = FileDirectory.GetFiles("*.png");
                foreach (FileInfo File in FileJpg)
                {

                    ImageList.Add(File.Name, File.FullName);
                    checkedListBox1.Items.Add(File.Name);
                    
                }
                foreach (FileInfo File in FileGif)
                {
                    ImageList.Add(File.Name, File.FullName);
                    checkedListBox1.Items.Add(File.Name);
                }
                foreach (FileInfo File in FileGif)
                {
                    ImageList.Add(File.Name, File.FullName);
                    checkedListBox1.Items.Add(File.Name);
                }
                foreach (FileInfo File in FileTif)
                {
                    ImageList.Add(File.Name, File.FullName);
                    checkedListBox1.Items.Add(File.Name);
                }
                foreach (FileInfo File in FilePng)
                {
                    ImageList.Add(File.Name, File.FullName);
                    checkedListBox1.Items.Add(File.Name);
                }
           
            }
        }
        private void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e)
        {
           /* int index = e.Index;
            pictureBox1.ImageLocation = ImageList[checkedListBox1.Items[index].ToString()].ToString();*/
            pictureBox1.ImageLocation = null;
            String s = folderBrowserDialog1.SelectedPath.ToString() + checkedListBox1.SelectedItem.ToString();
            MessageBox.Show(s.ToString());
            pictureBox1.ImageLocation = s; 
        }  
        private void Form1_Load(object sender, EventArgs e)
        {
            checkedListBox1.CheckOnClick = true;
        }

       
        private void checkedListBox1_SelectedIndexChanged_1(object sender, EventArgs e)
        {
            pictureBox1.Image = Image.FromFile(Path.Combine(folderBrowserDialog1.SelectedPath, checkedListBox1.Items[checkedListBox1.SelectedIndex].ToString()));
        }

        private void label2_Click(object sender, EventArgs e)
        {

        }
      }