You should add that line to the file to get the link to show up: /modules/classifieds/language/english/main.php: ($main_lang."_ADD_PHOTOS","Add Images");
(or to your main.php file in your preferred language folder i.e. /modules/classifieds/language/hungarian/main.php)
Also what have you set in preferences? Did you select group permissions for new kategories in module permissions?
Rune