Screenshots can be set up with other tracking related settings In Settings>Tracking Settings on organization level - for all your employee users. Additionally, you can change screenshots setup for one or several employees with employee settings override by clicking on employee name and then settings.
You can choose between the number of screenshots 1, 3, 6, 12, 24, or 30 screenshots in an hour per employee. Or you can disable screenshots entirely.
Screenshots are being taken in a randomized intervals.