This is not something we can do ourselves. The usual BP photos are not exactly placed on the stones in the cemetery maps, because of variance in the GPS signal processing.
That being said, sometimes the pins are erroneously located somewhere far from the grave site. In one case for me, the whole family plot got off into the adjoining housing development. If that happens you can send a message to BG support with the following information.
1. The URL for the person/record associated with the photo.
2. The image number if you can find it for sure.
3. The GPS, based on the Google Map position, of the wrong location, and
4. The GPS coordinates, based on the Google Map position, of the correct location.
In getting those GPS numbers, use your big screen computer, and zoom in as close as you can to the exact spots before reading and recording the GPS coordinates. Be as precise as possible.