一、nuget

    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.4" />

二、代码

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using SixLabors.ImageSharp.PixelFormats;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Processing;

namespace pdfdemo.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;

        public HomeController(ILogger<HomeController> logger)
        {
            _logger = logger;
        }
        public IActionResult Index()
        {
            var oriPath = $"{AppDomain.CurrentDomain.BaseDirectory}/1336349309181998041.png";
            var newpath = $"{AppDomain.CurrentDomain.BaseDirectory}/1336349309181998042.png";
            using (Image image = Image.Load(oriPath))
            {
                Rectangle cropArea = new Rectangle(0, 60, image.Width, image.Height-60);

                using (Image croppedImage = image.Clone(ctx => ctx.Crop(cropArea)))
                {
                    croppedImage.Save(newpath);
                }
            }
            return View();
        }

    }
}

原图：

截取后：