Example of KML file with images

KML example I took it from here. At the end my KML file gonna look like:

<?xml version="1.0" encoding="utf-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
  <Document>
    <name>Paths</name>
    <description>test</description>
    <Style id="red">
      <LineStyle>
        <color>7f0000ff</color>
        <width>4</width>
      </LineStyle>
      <PolyStyle>
        <color>7f0000ff</color>
      </PolyStyle>
    </Style>
    <Placemark>
      <name>Picture 1</name>
      <Snippet>This is a picture</Snippet>
      <description><![CDATA[Location: 19.8619823, 45.2547803<br> Elevation: 838,0 m<br> Time Created: 12/02/2021 09:57:23 BRT<br> <img src="IMG_20130710_140741.jpg"><br><img src="IMG_20130710_140741.jpg"><br>>]]></description>
      <Point>
        <coordinates>19.8619823, 45.2547803</coordinates>
      </Point>
    </Placemark>
    <Placemark>
      <name>Absolute Extruded</name>
      <description><![CDATA[Transparent green wall with yellow outlines]]></description>
      <styleUrl>#yellowLineGreenPoly</styleUrl>
      <LineString>
        <extrude>1</extrude>
        <tessellate>1</tessellate>
        <altitudeMode>absolute</altitudeMode>
        <coordinates>19.8619823, 45.2547803, 2357 
19.8683723, 45.2524965, 2357 
</coordinates>
      </LineString>
    </Placemark>
  </Document>
</kml>

The model:

using System.Xml;
using System.Xml.Serialization;

namespace CreateKmlFromFiles
{
  public class KmlModel
  {
    [XmlRoot("kml", Namespace = "http://www.opengis.net/kml/2.2")]
    public class Kml
    {
      public Document Document { get; set; }
    }

    public class Document
    {
      public string name { get; set; }

      public string description { get; set; }

      public Style Style { get; set; }

      [XmlElement("Placemark")]
      public Placemark[] Placemark { get; set; }

    }

    public class Style
    {
      [XmlAttribute("id")]
      public string id { get; set; }

      public LineStyle LineStyle { get; set; }
      public PolyStyle PolyStyle { get; set; }
    }

    public class LineStyle
    {
      public string color { get; set; }
      public string width { get; set; }
    }

    public class PolyStyle
    {
      public string color { get; set; }
    }

    public class Placemark
    {
      public string name { get; set; }
      public string Snippet { get; set; }
      public XmlCDataSection description { get; set; }
      public string styleUrl { get; set; }
      public Point Point { get; set; }
      public LineString LineString { get; set; }
    }

    public class LineString
    {
      public string extrude { get; set; }
      public string tessellate { get; set; }
      public string altitudeMode { get; set; }
      public string coordinates { get; set; }
    }

    public class Point
    {
      public string coordinates { get; set; }
    }
  }
}

Program:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using MetadataExtractor;
using MetadataExtractor.Formats.Exif;
using Newtonsoft.Json.Linq;
using Directory = System.IO.Directory;

namespace CreateKmlFromFiles
{
  class Program
  {

    static void Main(string[] args)
    {

      StringBuilder sb = new StringBuilder();
      foreach (string file in Directory.GetFiles(@"C:\someFilesWithGpsLocations"))
      {
        JObject myJObject = JObject.Parse(File.ReadAllText(file));
        sb.Append($"{myJObject["lng"]}, {myJObject["lat"]}, 2357 {Environment.NewLine}");
      }

      KmlModel.Kml kmlModel = new KmlModel.Kml
      {
        Document = new KmlModel.Document
        {
          name = "Paths"
          , description = "test"
          , Style = new KmlModel.Style
          {
            id = "red"
            , LineStyle = new KmlModel.LineStyle
            {
              color = "7f0000ff"
              , width = "4"
            }
            , PolyStyle = new KmlModel.PolyStyle
            {
              color = "7f0000ff"
            }
          }
          , Placemark = new KmlModel.Placemark[]
          {
            new()
            {
              name = "Picture 1"
              , Snippet = "This is a picture"
              , description = new XmlDocument().CreateCDataSection(
                "Location: 19.8619823, 45.2547803<br> Elevation: 838,0 m"
                + "<br> Time Created: 12/02/2021 09:57:23 BRT"
                + "<br> <img src=\"IMG_20130710_140741.jpg\">" 
                + "<br><img src=\"IMG_20130710_140741.jpg\"><br>>"
              )
              , Point = new KmlModel.Point
              {
                coordinates = "19.8619823, 45.2547803"
              }
            }, 
            new()
            {
              name = "Absolute Extruded"
              , description = new XmlDocument().CreateCDataSection("Transparent green wall with yellow outlines")
              , styleUrl = "#yellowLineGreenPoly"
              , LineString = new KmlModel.LineString
              {
                extrude = "1"
                , tessellate = "1"
                , altitudeMode = "absolute"
                , coordinates = sb.ToString()
              }
            }
          }
        }
      };

      TextWriter txtWriter = new StreamWriter
      (
        Path.ChangeExtension
        (
          System.Reflection.Assembly.GetEntryAssembly()?.Location
          , ".kml"
        ) ?? string.Empty);

      XmlSerializerNamespaces ns = new XmlSerializerNamespaces();

      ns.Add("", "http://www.opengis.net/kml/2.2");

      XmlSerializer xmlSerializer = new XmlSerializer(typeof(KmlModel.Kml));
      xmlSerializer.Serialize(txtWriter, kmlModel, ns);

      txtWriter.Close();
    }
  }
}

Difference between this example, and this one, is that Placemark is now declared as list of Placemarks:

[XmlElement("Placemark")]
public Placemark[] Placemark { get; set; }

and description:

public XmlCDataSection description { get; set; }

where I had to create CDATA section, like:

description = new XmlDocument().CreateCDataSection("Transparent green wall with yellow outlines")