C# 即使使用正确的using指令，对System.Drawing.Image的引用也是未知的

我有以下代码从PowerPoint文件中提取和保存图像：

public static void GetImages()
{
    var doc = PresentationDocument.Open(@"D:\Peak Sourcing\Work\ppt_test\presenting.ppt", true);
    var presentationPart = doc.PresentationPart;
    var slidePart = presentationPart.GetPartsOfType<SlidePart>().FirstOrDefault();
    var imagePart = slidePart.GetPartsOfType<ImagePart>().FirstOrDefault();
    var stream = imagePart.GetStream();
    var img = Image.FromStream(stream);
    img.Save(@"D:\Peak Sourcing\Work\ppt_test\test-output.png");
}

如何修复此问题？

检查System.Drawing.dll引用是否存在！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using System.Text;
using System.IO;
using PowerPoint = Microsoft.Office.Interop.PowerPoint;
using Microsoft.Office.Interop.PowerPoint;
using Microsoft.Office.Core;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using DocumentFormat.OpenXml.Presentation;
using DocumentFormat.OpenXml.Packaging;
using System.Drawing;