图片

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

namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        Graphics gg;
        Point a;
        Point b;
        int k = 0;
        string file;
        string file2;
        string[] arr;
        public Form1()
        {
            InitializeComponent();
            gg = pictureBox1.CreateGraphics();
        }

        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            a = new Point(e.X,e.Y);
         

        }

        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                b = new Point(e.X, e.Y);
                Rectangle r = new Rectangle(a, new Size(b.X - a.X, b.Y - a.Y));

                gg.DrawRectangle(new Pen(Color.Red), r);
                gg.FillRectangle(Brushes.Red, new Rectangle(a, new Size(b.X - a.X, b.Y - a.Y)));
              
            }
        }

        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog f = new FolderBrowserDialog();
            if(f.ShowDialog()==DialogResult.OK)
            {
                 file = f.SelectedPath;
            }
            k = 1;
            arr = System.IO.Directory.GetFiles(file);

            Bitmap bm = new Bitmap(arr[0]);
            Image myImage = Image.FromHbitmap(bm.GetHbitmap());
            this.pictureBox1.Image = myImage;
          
        }

        private void button2_Click(object sender, EventArgs e)
        {
           if(k<arr.Length-1)
           {
               k++;
            Bitmap bm = new Bitmap(arr[k]);
            Image myImage = Image.FromHbitmap(bm.GetHbitmap());
            this.pictureBox1.Image = myImage;
          
           }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (k >=1)
            {
                k--;
                Bitmap bm = new Bitmap(arr[k]);
                Image myImage = Image.FromHbitmap(bm.GetHbitmap());
                this.pictureBox1.Image = myImage;
              
            }
        }

        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog f = new FolderBrowserDialog();
            if (f.ShowDialog() == DialogResult.OK)
            {
                file2 = f.SelectedPath;
            }
         
        }

        private void button3_Click(object sender, EventArgs e)
        {
            pictureBox1.Image.Save(file2 + "//" + (k + 1).ToString() + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
        }

        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            b = new Point(e.X, e.Y);

            //Graphics g = Graphics.FromImage(pictureBox1.Image);
            //g.FillRectangle(Brushes.Red, new Rectangle(a, new Size(b.X - a.X, b.Y - a.Y)));
            //g.Dispose();

            pictureBox1.Invalidate();
        }
    }
}