Можно использовать

assets/CatalogAsset.php

+<?php
+/**
+ * @author Semenov Alexander <semenov@skeeks.com>
+ * @link http://skeeks.com/
+ * @copyright 2010 SkeekS (СкикС)
+ * @date 12.03.2015
+ */
+
+namespace skeeks\modules\cms\catalog\assets;
+use skeeks\cms\base\AssetBundle;
+
+/**
+ * Class SliderAsset
+ * @package skeeks\modules\cms\slider\assets
+ */
+class CatalogAsset extends AssetBundle
+{
+    public $sourcePath = '@vendor/skeeks/cms-module-catalog/assets';
+
+    public $css = [];
+    public $js = [];
+    public $depends = [];
+}

config/main.php

@@ -28,22 +28,25 @@ return [
                     [
                         [
                             "label" => "Товары",
-                            "url"   => ["catalog/admin-product"]
+                            "url"   => ["catalog/admin-product"],
+                            "img"       => ['\skeeks\modules\cms\catalog\assets\CatalogAsset', 'icons/product.png']
                         ],
 
-                        [
+                        /*[
                             "label" => "Типы товаров",
                             "url"   => ["catalog/admin-types-product"]
-                        ],
+                        ],*/
 
                         [
                             "label" => "Свойства товаров",
-                            "url"   => ["catalog/admin-properties-product"]
+                            "url"   => ["catalog/admin-properties-product"],
+                            "img"       => ['\skeeks\modules\cms\catalog\assets\CatalogAsset', 'icons/product-properties.png']
                         ],
 
                         [
                             "label" => "Группы свойств товаров",
-                            "url"   => ["catalog/admin-group-properties-product"]
+                            "url"   => ["catalog/admin-group-properties-product"],
+                            "img"       => ['\skeeks\modules\cms\catalog\assets\CatalogAsset', 'icons/product-propertirs-group.png']
                         ],
 
                     ]