Is the pictures public domain or how is the copyright permissions ?

Hi Linn,
Most of the photos are from the architect (firm)'s website and are for inspirational purposes only. The copyright remains with the architects and their respective photographers.
However, there are also photos that were sourced from the public domain (Wikimedia) and stock photo websites. If you check the bottom of the info bar for each photo, you will find a References tab. If you click that, you will see more info on each photo.