WPF

...
xmlns:myViewModel="clr-namespace:....ThisViewModel"

<TextBlock Text="{Binding Path=LengthProperty.Name}" .../>
<TextBlock Text="{Binding Path=LengthProperty.Value}" .../>
<TextBlock Text="{Binding Path=LengthProperty.UOM}" .../>

public partial class TreeNode : UserControl
{
    public TreeNode()
    {
        InitializeComponent();
    }

    public string Header
    {
        get { return txtNodeHeader.Text; }
        set { txtNodeHeader.Text = value; }
    }

    public Image Image
    {
        get { return imgNodeImage; }
        set { imgNodeImage = value; }
    }
}

<UserControl x:Class="TreeViewPicture.TreeNode" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
mc:Ignorable="d"
d:DesignHeight="20"
d:DesignWidth="150">
    
    <StackPanel Orientation="Horizontal">
        <Image Name="imgNodeImage" Width="16" Height="16" />
        <Separator Width="10" />
        <TextBlock Name="txtNodeHeader" Text="NodeHeaderText" />
    </StackPanel>
    
</UserControl>

<Window x:Class="TreeViewPicture.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:TreeViewPicture"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TreeView Name="tvTree">
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding Nodes}" DataType="{x:Type local:ImageNode}">
                    <Grid>
                        <!--<TextBlock Text="{Binding Header}" />-->
                        <local:TreeNode Header="{Binding Header}" Image="{Binding Image}" />
                    </Grid>
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
    </Grid>
</Window>

public abstract class Node
    {
        ObservableCollection<Node> nodes = new ObservableCollection<Node>();
        Image image;
        string header;

        public Node(string header, BitmapImage image)
        {
            this.header = header;
            this.image = new Image();
            this.image.Width = 16;
            this.image.Source = image;
        }

        public string Header
        {
            get { return header; }
        }

        public Image Image
        {
            get { return image; }
        }

        public ObservableCollection<Node> Nodes
        {
            get { return nodes; }
        }
    }

public class Server : Node
{
    public Server(string header, BitmapImage image) : base (header, image)
    {
    }
}

public class Gateway : Node
{
    public Gateway(string header, BitmapImage image) : base(header, image)
    {
    }
}

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

    public partial class MainWindow : Window
    {
        BitmapImage serverImage;
        BitmapImage gatewayImage;

        public MainWindow()
        {
            InitializeComponent();
            InitImages();

            Server server = new Server("Server", serverImage);
            Gateway gateway = new Gateway("Gateway", gatewayImage);

            ObservableCollection<Node> nodes = new ObservableCollection<Node>();
            
            nodes.Add(server);
            server.Nodes.Add(gateway);
            tvTree.ItemsSource = nodes;
        }

        private void InitImages()
        {
            serverImage = new BitmapImage();
            serverImage.BeginInit();
            serverImage.UriSource = new Uri(@"C:\Users\TheUser\Images\Server.png");
            serverImage.EndInit();

            gatewayImage = new BitmapImage();
            gatewayImage.BeginInit();
            gatewayImage.UriSource = new Uri(@"C:\Users\TheUser\Images\Gateway.png");
            gatewayImage.EndInit();
        }
    }