On my iPhone, I normally turn off Location Services on the Camera for privacy.

I turned it in today for a specific event, but not before I had taken several photos without location information.

How can I retroactively fill in the location information? I know exactly where each photo was taken, and even have pins bookmarked in Maps for each location.

It needs to be lossless, no JPEG recompression. An iOS app would be nice, or a Windows/Mac solution.