Another photo from the same place, taken 32 years ago, seems to show a ghost at a window too.
This link is a Yahoo news page, which tend to scroll away after a few days. I haven't found a more permanent link yet.
I'd like to visit the place and see whether there are any accessible areas behind those windows. It's a ruin so it's not certain from the photos, although the window in the earlier one (previous post) was barred, and there's no reason for that unless it's to stop visitors falling through it. So in that one, there probably is an accessible area. In the 'new' image, it's not so clear. Accessible areas raise the possibility of someone wandering past and being photographed unintentionally - or of someone fooling around.
There are similarities in the images, but neither is clear enough to be sure. Maybe better quality copies will appear eventually. I hope so because if the images are very similar and taken 32 years apart, it will be stronger evidence. With luck, more people will come forward with more images.
Anyway, must get back to my own investigations. I have been lax for too long!