Not really pertaining to GPS and pics but I remember reading something a few years back from a guy that claimed to work for a large cellular provider. He said the only way to truly disable GPS is to remove the battery. He went on to say that a cell phone can be tracked even when it's powered off and that the company he worked for only needs a court order to [legally] enable GPS tracking. Apparently this was not all that uncommon...
Not only can they activate the GPS at will...
but
any time your battery is in your cellphone, even if the cellphone is powered down, the cell company can activate the mic and camera.
There was a sting operation run on the mafia several years ago where surveillance was carried out through cellphones in such a manner.