The Phantasm Camera Riddle

Stuart is a lone photographer based in Dunfermline, Scotland.
His specialty; post-mortem photography.
At the beginning of the 20th century, the custom of photographing the dead is at its dawn, but Stuart is an old-fashioned war veteran. He keeps the practice alive.
His life starts changing after his brother's death. Stuart suddenly gets flashbacks of the past long forgotten. The dead subjects on his photos turn out distorted, as if moved...
He meets Regina, a photography enthusiast herself. The two engage themselves in photographing crime scenes.
More strange occurrences appear in their photos. Stuart is scared that someone is threatening him and his distant family. He aims to find a rational explanation while the ghosts from the photos are haunting him in his dreams.
They're warning him there's something more dangerous than them he should be afraid of...