Mac OS X Quarter Hour Timer via This Supervising Crontab (Ideally suited for MAMP, and left running) - RJM Programming - June, 2016

$ sudo crontab -e
/usr/bin/php /Applications/MAMP/htdocs/HTMLCSS/quarter_hour_timer.php # 0,15,30,45 * * * * /usr/sbin/screencapture -Cd -tjpg /Applications/MAMP/htdocs/screen-`date +"\%Y\%m\%d-\%H\%M"`.jpg

Optionally fill in your Name: Email Times From Earliest Below ... To Latest Below ...