using System.Drawing;

namespace kq.Utils
{
 public static class CommonTools
 {

  public static Bitmap getVerifyCode(Bitmap srcBmp, Rectangle rectangle)
  {
   //初始化一個(gè)bmp對(duì)象，90代表圖片的寬度，37代表高度
   Bitmap bmp = new Bitmap(90, 37);
   Graphics g = Graphics.FromImage(bmp);
   g.DrawImage(srcBmp, 0, 0, rectangle, GraphicsUnit.Pixel);
   return bmp;
  }
 }
}

using kq.Utils;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using System.Drawing;

namespace kq
{
 class Program
 {
  static void Main(string[] args)
  {
   try
   {
    string screenImg = @"d:\screenImg.png";

    Bitmap fromBmp = new Bitmap(screenImg);
    Rectangle section1 = new Rectangle(936, 523, 90, 37);

    Bitmap bmp = CommonTools.getVerifyCode(fromBmp, section1);

    bmp.Save(@"d:\驗(yàn)證碼.bmp");
   }
   catch (System.Exception e)
   {
    System.Console.WriteLine(e.Message);
   }

  }
 }
}