Bhutan offers immense opportunities for photography especially during outdoor sightseeing trips.
However you should check with your guide before taking pictures or filming inside Dzongs, temples, monasteries and religious institutions as in some area photograph/filming is not permitted.
You are free to capture images of the landscape, the panoramic views of the mountain ranges, rural life, flora and fauna, distinctive Bhutanese architecture and the exterior of Dzongs and Chortens in particular.