temp not recreate existing

app/models/photo.rb

@@ -93,6 +93,7 @@ class Photo < ActiveRecord::Base
 
 
   def create_thumbnails
+    return if File.exists?(APP_CONFIG[:thumbs_path] + self.album.path + "/" + self.id.to_s + "_collection" + self.extension)
     ImageScience.with_image(self.path_original) do |img|
         puts "thumb " + self.path_original
         img.cropped_thumbnail(200) do |thumb|