Taking Pictures During House Inspections

It wouldn't be all that common, but there's nothing in the legislation that would specifically disallow it in general, so it's not likely to be an issue unless the agent is doing something that would be particularly intrusive or potentially illegal (e.g. digging through the tenant's drawers or other personal belongings and photographing them specifically, entering the property unannounced, recording or taking photos of the tenants themselves when they'd ordinarily expect to have a right to privacy, etc.). If they're just snapping a quick photo of the rooms or some closeups of potential issues that might need the landlord's attention during a prearranged inspection, that's no more of a violation of privacy than the landlord themselves looking at the place in person. It could just be the landlord wants some visual evidence of the inspection or a record of the state of the place from their agent.

Inspections every three months is what the RTB recommends, so that frequency isn't an issue either.