4images one: table-prefix = 4images_prefix1
4images two: table-präfix = 4images_prefix2
4images one or two
in includes/constant.php:
define('USERS_TABLE', $table_prefix.'users');
replace with:
$table_prefix2 = "4images_prefix2";
define('USERS_TABLE', $table_prefix2.'users');
4images two times, in one database and two prefixes!