I think the most likely scenario is that he is now an ex-JW. Watchtower loves to stigmatize. They likely stigmatize as "spiritually unclean" any publication the production of which was contributed to by anyone that is now an ex-JW. Remember what happened to all the publications authored by Raymond Franz? When it's a photo appearance, they edit the person out of the photo.
There could also be legal concerns as well. A JW who disassociates might not want his picture to continue being featured in Watchtower literature, giving the impression that he is still affiliated with the organization. Some might threaten legal action if Watchtower does not remove their image from their literature.