It was snapped just days before Lomu died suddenly on November 18, a day after he returned to Auckland.
The happy family portrait, which features the couple's two young sons Brayley and Dhyreille, has a simple, touching hashtag "FlyHighDaddy".
Well-wishers have commented on the recent public post with messages of condolence and support.
"Thank you for sharing Jonah with the world," posted Folola Lua.
Kerry Sikora wrote: "Beautiful picture of a beautiful family, thinking of you all so much. x"
Kilioni Mafi wrote: "He will always be your guardian angel to watch over you n the boys Ofa lahi atu."
Two public memorials were held to farewell Lomu before a funeral service was held at the Church of Jesus Christ of Latter-day Saints last Tuesday.
The service included a musical dedication from the Lomu brothers who sang a duet "I am a child of God".