To disable the auto-dimming display when showing dark images do the followin:
- Go to the power options via Control Panel or Tray Icon (the one with the battery symbol), click it and select "More power options".
- Select the Power Plan you wish to change and click "Change plan settings".
- Click on "Change advanced power settings" at the bottom, scroll down and expand the list "display".
- Look for "Enable Adaptive Brightness", expand the option and turn off the desired option.
