If that was the case imagine what every US president would have to go through after being newly elected/sworn in. To the best of my knowledge all ambassadors give their credentials only once to the sitting head of state. A new head of state does not get the credentials of the sitting ambassadors.
It was a major event that photographers were allowed in. Beatrix banned them throughout her reign. The new king may have only let them in because it was his first time, but i hope he'll appoint something like a courtphotographer. The pictures could be made public through the RVD (RijksVoorlichtingsDienst = the official government service providing the media with information not just of the Royal House but also about the cabinet and government).