scrot 0.8-18 (amd64 binary) in ubuntu bionic

 scrot (SCReen shOT) is a simple command line screen capture
 utility that uses imlib2 to grab and save images. Multiple
 image formats are supported through imlib2's dynamic saver
 modules.
 .
 Some features of the scrot:
   - support to multiple image formats (JPG, PNG, GIF, etc.).
   - optimization of the screen shots image quality.
   - capture a specific window or a rectangular area on the
     screen with the help of switch.
 .
 scrot also can be used to monitor a desktop PC in admin absent
 and register unwanted activities.