what did you use to take pictures from your webcam periodically? If it's a python script, could you please share your code with us?
https://github.com/zacstewart/dotfiles/blob/master/git/.git_...
https://gist.github.com/4477040 is the cron script I use on a 10 min interval.
There might be other ways to do this now days, but i've used this successfully for a few years.