If you get some nice pictures, instead of putting one in a frame, you could put it on a picnic/beach blanket:
https://www.bedbathandbeyond.com/store/product/time-to-smile-photo-beach-blanket/5192820
And put others on beach towels with personalized messages (date, Happy Retirement, etc.). Several places do this, including:
https://photos3.walmart.com/category/612-full-photo--designed-beach-towels