New pics are for a new season anyway! New pics can often create a new view of your property.
If you took the photos, then there is no problem using them again. MLS does not have any rules preventing the reuse of photos. The copyright issue comes up if the photos belong to the agent that originally listed your home, and then you hire a different agent when you relist it. That agent cannot use the previous agents photos. Besides being unethical, it's just plain lazy.
Armstrong Field Real Estate