How to change the utilized grapics library after install?

Using Neos & Flow Installation & Deployment
1

Hi,

how can I change the utilized graphics library after install?
E.g. from PHP GD Library to GraphicsMagick or ImageMagick?

Best Regards,

Thomas

2 
TYPO3:
  Imagine:
    driver: 'Gd'

Look for that Setting.