Ghost of Lord Combermere at Combermere Abbey

The story according the official website describes the events surrounding the photograph as follows:

…Lord Combermere passed away in 1891; and whilst his funeral was taking place on the 5th December at St. Margaret’s church… his sister Lady Sutton was renting the Abbey for herself and her siblings to stay, took a photo of the wonderful Combermere Library with a long exposure camera…

Corbet recorded that the exposure of the photograph took around an hour, and when the photo was developed a year later Sybell found a startling sight – there was a transparent image of a man’s upper body sitting in one of the chairs in the library.

Lord Combermere’s children noted the apparition’s likeness to their late father, and the chair the spectre seems to be sitting in was indeed his favorite…

Could this be a real photograph of someone that’s deceased and a sign that the entire place is haunted?