We were told no photos inside. IIRC there are signs up that said the same.
Very well organised tour and well worth the visit. They must have hundreds of volunteers working there. We didn't book ahead and had no problem getting right in.
Excellent workmanship for sure. My expectations were pretty high though, my parents had the opportunity to tour the Cardston temple some years ago after a major reno and they said it was spectacular.
I had to fight off the temptation to check the temperature of the water in the baptismal font.
Some of the carpets have hand-carved designs in them, I can't imagine the work that went into those.