It looks like these are pictures of the 1948 Queen's Day parade in Amsterdam (which actually took place the day before Queen's Day). You can see a video of it here. The car with Queen Wilhelmina which is in picture 3 and 4 is visible from 1:26 in the video. You can also see the escort on the motorbikes.

The 1948 Queen's Day was very special, as Queen Wilhelmina had already announced that she would abdicate later in the year. It was supposed to be a sober event, as the country was still recovering from the war, but since it would be the last Queen's Day with Wilhelmina as Queen the people came out in droves. Wilhelmina's heir, Juliana, is visible in picture 5 with her husband Bernhard (it's a bit grainy and I haven't been able to find confirmation that they were actually in the parade, but it does look like them and it is customary for the heir-apparent to be present in the parade). Other pictures just show more of the parade. I'm not sure who is in picture 12; the kid might be princess Beatrix or princess Irene (grandchildren of Queen Wilhelmina).