You should visit Vaishno Devi and i think you can take pictures but not at all places. Infact you can take anything with you till you reach the bhawan area where you need to deposit you leather items and electronic items before joining the queue.
You are required to keep your belongings in the cloak room for security purposes once you are in bhawan area. I would suggest you to keep a good camera with you while on the track as the mother nature provides you many of its beautiful and exotics scenes up there which are worth enough to capture for a lifetime memory!