Index: lib/technoweenie/attachment_fu.rb
===================================================================
--- lib/technoweenie/attachment_fu.rb	(revision 1098)
+++ lib/technoweenie/attachment_fu.rb	(working copy)
@@ -68,7 +68,7 @@
           with_options :foreign_key => 'parent_id' do |m|
             m.has_many   :thumbnails, :class_name => attachment_options[:thumbnail_class].to_s
             m.belongs_to :parent, :class_name => base_class.to_s
-          end
+          end unless options[:thumbnails].empty?
           before_destroy :destroy_thumbnails
 
           before_validation :set_size_from_temp_path