Source of images:

* error16x16.png - https://commons.wikimedia.org/wiki/File:Emblem-important.svg
* approved16x16.png - https://commons.wikimedia.org/wiki/File:Check-green.svg
* rejected16x16.png - https://commons.wikimedia.org/wiki/File:Button_cancel.svg
* processing16x16.png - https://commons.wikimedia.org/wiki/File:Appointment.svg
* untouched16x16.png - empty image, PD-trivial