diff --git a/app/models/collection_item.rb b/app/models/collection_item.rb
index a412f883bd5608a70d4185d758d3aa4a9f335a16..4fc48636bdb07fefc3468a79dc6dce01bafcb704 100644
--- a/app/models/collection_item.rb
+++ b/app/models/collection_item.rb
@@ -24,4 +24,9 @@ class CollectionItem < ApplicationRecord
   def recipient
     collection
   end
+
+  def thumbnail
+    collectionable_type == 'LearningObject' ?  LearningObject.find(collectionable_id).default_thumbnail : Collection.find(collectionable_id).thumbnail
+  end
+
 end
diff --git a/app/serializers/collection_serializer.rb b/app/serializers/collection_serializer.rb
index 36904b88abb280581edc8d255e5c904109409d67..01887f060a38bb59b804d4804106e93f0dc3cc39 100644
--- a/app/serializers/collection_serializer.rb
+++ b/app/serializers/collection_serializer.rb
@@ -13,7 +13,15 @@ class CollectionSerializer < ActiveModel::Serializer
     object.complained? current_user
   end
 
-  attributes :id, :name, :created_at, :updated_at, :description, :privacy, :score, :likes_count, :liked, :reviewed, :complained, :review_average, :thumbnail
+  def items_thumbnails
+    thumbs = []
+    object.collection_items[0..3].each do | t |
+      thumbs << t.thumbnail
+    end
+    thumbs
+  end
+
+  attributes :id, :name, :created_at, :updated_at, :description, :privacy, :score, :likes_count, :liked, :reviewed, :complained, :review_average, :thumbnail, :items_thumbnails
   belongs_to :owner
   has_many :tags
   has_many :subjects