I'm guessing they do as they reserve the right to use the photos for their advertisement etc. so would have to keep copies in order to access them, although how easy it is for them to re-release or how willing they are is another matter; contact them directly to find out, Twitter and Facebook are good options but if you click on the link it's give you a few options - Contact Airbnb
If you delete photographer uploaded photos from your listing, then they are gone. You can however preserve the remaining photographer captured images by right click and saving to your laptop or tablet.
Airbnb keeps the photographer uploaded photos where you see them and can't provide deleted ones.