I can!
Each church has classrooms (also containing no religious imagery), a Chapel (generally not containing artwork or other images) and a gym. Artwork can generally be found in the hallways, depicting Jesus or other religious figures. The gospel is taught in all of these places (ok maybe not in the hall), and religious images can be checked out from the ward library for use as visual aids. There isn't a rule against religious artwork or anything, it's just that the classrooms are for function, not decoration, and to hang framed artwork in hundreds of thousands of classrooms around the world would be a grievous financial burden, I think.
It is important to note that although you may not have seen the chapel, it is generally attached to the gym, divide by a sliding divider. Often if there are too many people in the chapel, they will open the divider to allow expanded capacity. The worship services take place in the chapel, not in the gym.
The ward buildings have gyms to encourage members and those not of our faith to get together and play sports, enjoying comraderie and sportsmanship. They serve places for wedding receptions, youth dances and other activities (including scout courts of honor). All of these uses and others are well served even without artwork, and artwork may even be endangered by flying basketballs, etc. It's not a disrespect for Christ or other biblical figures, just an accommodation of the intended function of the area. Our worship isn't as centered on statues and other images as some other faiths, but more on the doctrine and study of the gospel, and most centrally the actual person of Christ, rather than the symbol of him. I hope your son enjoyed his meeting.
