C#でデザインパターン「Visitorパターン」

/// <summary>
/// Visitorパターンのサンプルコード
/// </summary>
interface IVisitor
{
    // void Visit(IImage img);
    void Visit(Png img);
    void Visit(Jpeg img);
    void Visit(Grayscale img);
}
interface IImage
{
    void Accept(IVisitor visitor);
}
class Png : IImage
{
    public int Width {get;}
    public int Height {get;}
    public readonly int DEPS = 4;
    public Png(int width, int height)
    {
        Width = width;
        Height = height;
    }
    public void Accept(IVisitor visitor) => visitor.Visit(this);
}
class Jpeg : IImage
{
    public int Width {get;}
    public int Height {get;}
    public readonly int DEPS = 3;
    public Jpeg(int width, int height)
    {
        Width = width;
        Height = height;
    }
    public void Accept(IVisitor visitor) => visitor.Visit(this);
}
class Grayscale : IImage
{
    public int Width {get;}
    public int Height {get;}
    public readonly int DEPS = 1;
    public Grayscale(int width, int height)
    {
        Width = width;
        Height = height;
    }
    public void Accept(IVisitor visitor) => visitor.Visit(this);
}
class PixcelCountVisitor : IVisitor
{
    /*
    public void Visit(IImage img)
    {
        int result = 0;

        switch (img)
        {
            case Png png:
                result = png.Width * png.Height * png.DEPS;
                break;
            case Jpeg jpg:
                result = jpg.Width * jpg.Height * jpg.DEPS;
                break;
            case Grayscale gray:
                result = gray.Width * gray.Height * gray.DEPS;
                break;
            default:
                throw new NotSupportedException ($"未対応{img.GetType().Name}");
        }

        Console.WriteLine($"Picel:{result}");
    }
    */
    public void Visit(Png png)
    {
        int result = png.Width * png.Height * png.DEPS;
        Console.WriteLine($"Png Picel:{result}");
    }

    public void Visit(Jpeg jpg)
    {
        int result = jpg.Width * jpg.Height * jpg.DEPS;
        Console.WriteLine($"Jpeg Picel:{result}");
    }

    public void Visit(Grayscale gray)
    {
        int result = gray.Width * gray.Height * gray.DEPS;
        Console.WriteLine($"Grayscale Picel:{result}");
    }}

public class Program
{
    static public void Main()
    {
        IImage png = new Png(256, 128);
        IImage jpg = new Jpeg(256, 128);
        IImage gray = new Grayscale(256, 128);

        List<IImage> images = [png, jpg, gray];

        PixcelCountVisitor pixcelCountVisitor = new();

        foreach(IImage img in images)
        {
            img.Accept(pixcelCountVisitor);
        }
    }    
}