There are some additional settings in the $CAPTCHA_INIT array when using the GarbageCollector:
'counter_filename' => ''
// string: absolute filename for textfile which stores current counter-value.
!! Needs read- & write-access !!
'prefix' => 'hn_captcha_'
// string: prefix for the captcha-images, is needed to identify the files in shared tempfolders
'collect_garbage_after' => 20
// integer: the garbage-collector run once after this number of script-calls.
Every script call count up the value in counterfile, when reaching this value, the grabage-collector runs and clean all files which are older than ->
'maxlifetime' => 60
// integer: only imagefiles which are older than this amount of seconds will be deleted
After that you can instantiate the class:
$captcha = new hn_captcha_X1 ( $CAPTCHA_INIT );
For more details please view the examplefile ('hn_captcha.x1.example.php').