It depends on who took the photos and what agreements are in place.
The photos belong to whoever took them unless the original photographer signed an agreement conveying ownership to someone else. The owner could be the previous homeowner, the previous listing broker, or an independent photographer.
You must secure either a license to use or the rights to the photos from the owner of the photos. Texas REALTORS® offers several forms, including the Model Work Made for Hire Agreement establishing the broker as owner and author of photos taken by another at the time the photos are taken, the Model License Agreement for assigning use licenses for photos, and the Model Assignment Agreement for assigning the rights to photos.
If you, the listing agent, had taken the photos when the property was previously listed and you are now engaged by the current property owners to list the property again, you can reuse the photos you took previously, since you are the owner of those photos.
Note that it is in the agent’s best interest to ensure the photos accurately depict the property in its current state, as significant changes could have occurred since the photos were taken.