POC for replacing inline images with separate http requests

AngleCheck.cs

using System;
using System.Linq;
using AngleSharp.Html.Parser;

namespace ParsingCheck
{
    public class AngleCheck
    {
        // POC for replacing inline images with separate http requests
        // AngleSharp v0.16.1
        public static void Parse(string html)
        {
            var parser = new HtmlParser();
            var doc = parser.ParseDocument(html);
            var imgs = doc.QuerySelectorAll("img")
                .Where(x => x.HasAttribute("src") && x.GetAttribute("src")!.StartsWith("data:"));
            var i = 1;

            // x.HasAttribute("src")
            // x.Attributes["src"].Value

            foreach (var img in imgs)
            {
                Console.WriteLine($"src: {img.GetAttribute("src")}");
                img.SetAttribute("src", $"/api/{i}");
                img.SetAttribute("loading", "lazy");
                i++;
            }

            Console.WriteLine("== Result html");

            // avoid html,body tags for fragments
            Console.WriteLine(doc.QuerySelector("body")?.InnerHtml);
        }
   }
}

input.html

<p>
  <img src="x1">
</p>

<p>
  <img src="data:x1">
</p>
<div>
  <img data-src="data:x1">
</div>

<p>This is from stage server:</p><p><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAB4AAAAQQCAIAAACMTtFPAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAASdEVYdFNvZnR3YXJlAEdyZWVuc2hvdF5VCAUAAP+HSURBVHhe7L0JlF3VdebvtboTp51enX">

results.txt

src: data:x1
src: data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAB4AAAAQQCAIAAACMTtFPAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAASdEVYdFNvZnR3YXJlAEdyZWVuc2hvdF5VCAUAAP+H
SURBVHhe7L0JlF3VdebvtboTp51enX
== Result html
<p>
  <img src="x1">
</p>

<p>
  <img src="/api/1" loading="lazy">
</p>
<div>
  <img data-src="data:x1">
</div>

<p>This is from stage server:</p><p><img src="/api/2" loading="lazy">
</p>