OSX Launch Daemon for Periodic Screenshots
In the comments to the question you say &quot;But just want it to track what I'm spending my time doing&quot;.
Interpreting your underlying question as being how to track application usage, I will risk being downvoted for not answering your question as in its title.
I think that a large collection of screenshots is not the best way to track what you are doing. Certainly further analysis will be complex.
To track application usage, I use Keyboard Maestro with a one action macro.

This creates a CSV file with three fields: Date, Time and Application name.
That will provide application usage in a form which is amenable to further analysis.