diff --git a/app/serializers/collection_serializer.rb b/app/serializers/collection_serializer.rb
index 01887f060a38bb59b804d4804106e93f0dc3cc39..790640ffab30e1178ea168916c7abea4d218b16d 100644
--- a/app/serializers/collection_serializer.rb
+++ b/app/serializers/collection_serializer.rb
@@ -15,8 +15,11 @@ class CollectionSerializer < ActiveModel::Serializer
 
   def items_thumbnails
     thumbs = []
-    object.collection_items[0..3].each do | t |
-      thumbs << t.thumbnail
+    i = 0
+    while thumbs.size < 4 && i < object.collection_items.size do
+      t = object.collection_items[i].thumbnail
+      thumbs << t unless t.blank?
+      i=i+1
     end
     thumbs
   end