@Laura2592
If you has changed something and has made improviments, from my point of view it is necessary to take new photos. Being the listing better than it used to be before, the new pics will help to get more bookings and make the listing more attractive to the guests.
As what other guests have said, you can updated only some pictures if you want to.
I think it is not necessary to have professional photos taken by a professional photographer.
If you love taking pictures, you can take your own pictures that looks like professional.
In the Airbnb articles and in the internet there are losts of post and articles about taking good pictures.