That could be the culprit then, 15 seconds is a short time on a slow server. Can you do the .htaccess or php.ini in each directory trick to override the settings?
The workaround is to watermark the images on upload, not on display as is currently done.
That recalled my issue on Global Register = on, there is no effect even I had my own .htaccess or php.ini in each directory.
Well they are very hesitated to alter any parameter.
So can it be an option (feature) for us to choose the watermark method (on upload/on display) in the coming version of RSG2?