Show unity built-in images

BuiltInImagesWindow.cs

using System.IO;
using System.Linq;
using System.Reflection;
using UnityEditor;
using UnityEngine;

public class BuiltInImagesWindow : EditorWindow
{
    [MenuItem("Window/Built-in Images")]
    public static void ShowWindow()
    {
        GetWindow<BuiltInImagesWindow>().Show();
    }

    private string[] resourcePaths;

    private void OnEnable()
    {
        var type = typeof(EditorGUIUtility);
        var methodInfo = type.GetMethod("GetEditorAssetBundle", BindingFlags.Static | BindingFlags.NonPublic);
        var result = methodInfo.Invoke(methodInfo, null) as AssetBundle;

        //Only png & jpg
        resourcePaths = result.GetAllAssetNames()
            .Where(item => Path.GetExtension(item) == ".png"
                           || Path.GetExtension(item) == ".jpg").ToArray();
    }

    private float _scrollbarPos;

    private const float GridWidth = 64.0f;
    private const float GridHeight = 64.0f;
    private const float ScrollbarWidth = 16.0f;

    private void OnGUI()
    {
        var windowRect = position;
        GUILayout.BeginVertical();
        var height = 0.0f;
        var realHeight = 0.0f;
        var widthCount = (int) (windowRect.width / GridWidth);
        var start = resourcePaths.Length / widthCount * GridHeight * _scrollbarPos / 100.0f;
        for (var index = 0; index < resourcePaths.Length;)
        {
            realHeight += GridHeight;
            if (realHeight < start)
            {
                index += widthCount;
                continue;
            }

            if (height + GridHeight > windowRect.height)
            {
                break;
            }

            GUILayout.BeginHorizontal();
            var width = 0.0f;
            for (var innerIndex = 0; index < resourcePaths.Length && innerIndex < widthCount; index++, innerIndex++)
            {
                if (width + GridWidth > windowRect.width - ScrollbarWidth)
                {
                    break;
                }

                var resourcePath = resourcePaths[index];
                var texture = EditorGUIUtility.Load(resourcePath) as Texture2D;
                if (GUI.Button(new Rect(width, height, GridWidth, GridHeight), texture))
                {
                    Debug.Log(resourcePath);
                    GUIUtility.systemCopyBuffer = resourcePath;
                }

                width += GridWidth;
            }

            GUILayout.EndHorizontal();
            height += GridHeight;
        }

        GUILayout.EndVertical();
        _scrollbarPos = GUI.VerticalScrollbar(
            new Rect(windowRect.width - ScrollbarWidth, 0, ScrollbarWidth, windowRect.height), _scrollbarPos,
            1.0f, 0.0f, 100.0f);
    }
}