bug 937 fixed: makes sure a user won't see the thumbnail of a photo that has a

higher privacy level than user privacy level.

For an acceptable solution at performance level, I have implemented a cache:
for a given user, each album has a representative_picture_id. This cache also
avoids to perform numerous "order by rand()" SQL queries which is the case
when $conf['allow_random_representative'] = true;


git-svn-id: http://piwigo.org/svn/trunk@8802 68402e56-0260-453c-a942-63ccdbb3a9ee

install/piwigo_structure-pgsql.sql

@@ -514,6 +514,7 @@ CREATE TABLE "piwigo_user_cache_categories"
   "nb_images" INTEGER default 0 NOT NULL,
   "count_images" INTEGER default 0,
   "count_categories" INTEGER default 0,
+  "user_representative_picture_id" INTEGER,
   PRIMARY KEY ("user_id","cat_id")
 );