Uninstalled everything. Dropped database. Retrieved fresh WebCalendar-1.2.3.tar.gz. Clean install, no errors. Imported saved events. All working.
Enabled captcha.
On add-event page captcha image is show as blank block with correct file name property.
http://www.example.org/calendar/images/captcha/d41d8cd98f00b204e9800998ecf8427e.jpg
The .jpg file is exists but has size of 0kb.
PHP5 errors:
[05-Oct-2013 18:57:32 America/New_York] PHP Warning: imagejpeg(): Filename cannot be empty in /home/www/calendar/includes/classes/captcha/captcha.php on line 259
[05-Oct-2013 18:57:32 America/New_York] PHP Warning: Division by zero in /home/www/calendar/includes/classes/captcha/captcha.php on line 263
Ray Jones created the captcha.php script.
Is there anyone else who knows how to diagnose it?