<Window x:Class="BitmapTests.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:BitmapTests"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <ListView ItemsSource="{Binding Images}"
                  VirtualizingStackPanel.VirtualizationMode="Recycling"
                  VirtualizingStackPanel.CleanUpVirtualizedItem="ItemsControl_CleanUpVirtualizedItem">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <Image Source="{Binding Image50}" Width="50" HorizontalAlignment="Left" />
                        <TextBlock Text="{Binding Name}" Padding="10" />
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Grid>
</Window>

using System;
using System.Collections.ObjectModel;
using System.Diagnostics.Eventing;
using System.IO;
using System.Reflection;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace BitmapTests
{
    public partial class MainWindow : Window
    {
        private ImageModel _model;
        public MainWindow()
        {
            InitializeComponent();
            _model = new ImageModel(@"put your path here"); // TODO
            DataContext = _model;
        }

        private void ItemsControl_CleanUpVirtualizedItem(object sender, CleanUpVirtualizedItemEventArgs e)
        {
            ImageModel.Log("Clean '" + ((ImageObject)e.Value).FilePath + "' pressure: " + ImageModel.GetMemoryPressureMega());
        }
    }

    public class ImageObject
    {
        private ImageSource _image;

        public ImageObject(string path)
        {
            FilePath = path;
            Name = Path.GetFileName(path);
        }

        public string Name { get; }
        public string FilePath { get; }

        public ImageSource Image50
        {
            get
            {
                if (_image == null)
                {
                    _image = ImageModel.CreateImageForThumbnail(FilePath, 50);
                    ImageModel.Log("Load '" + FilePath + "'. pressure: " + ImageModel.GetMemoryPressureMega());
                }
                return _image;
            }
        }
    }

    public class ImageModel
    {
        private static EventProvider _trace = new EventProvider(new Guid("9f704449-67aa-4888-8484-3fdfb6ce4854"));
        private static FieldInfo _totalMemory;

        public ImageModel(string directoryPath)
        {
            if (directoryPath == null)
                throw new ArgumentNullException("directoryPath");

            Log("Rendering Tier: " + (RenderCapability.Tier >> 16));

            Images = new ObservableCollection<ImageObject>();
            foreach (var file in Directory.EnumerateFiles(directoryPath))
            {
                string ext = Path.GetExtension(file).ToLowerInvariant();
                if (ext != ".gif" && ext != ".jpg" && ext != ".jpeg" && ext != ".png")
                    continue;

                var im = new ImageObject(file);
                Images.Add(im);
            }
        }

        public ObservableCollection<ImageObject> Images { get; private set; }

        public static void Log(string value)
        {
            _trace.WriteMessageEvent(value);
        }

        public static long GetMemoryPressureMega()
        {
            if (_totalMemory == null)
            {
                _totalMemory = typeof(Clipboard).Assembly.GetType("MS.Internal.MemoryPressure").GetField("_totalMemory", BindingFlags.Static | BindingFlags.NonPublic);
            }
            return (long)_totalMemory.GetValue(null) / 1000000;
        }

        public static ImageSource CreateImageForThumbnail(string path, int decodePixelWidth)
        {
            var bmp = new BitmapImage();
            using (var stream = File.OpenRead(path))
            {
                bmp.BeginInit();
                bmp.StreamSource = stream;
                if (decodePixelWidth > 0)
                {
                    bmp.DecodePixelWidth = decodePixelWidth;
                }
                bmp.CacheOption = BitmapCacheOption.OnLoad;
                bmp.EndInit();
                bmp.Freeze();
                return bmp;
            }
        }
    }
}