In Japanese, "shinrei shashin" (心霊写真) means "spirit or ghost photography". It's usually accidental, and some people think it's real. Others don't. This notion isn't only Japanese and exists pretty much wherever there are cameras. Oh, and dead people.
Often these pics end up being creepy photobombs, with unsettling images discovered in the background. You know, a reflection in the mirror or something out of The Ring. Here's a sample:
This is very much a thing in Japan and pops up in movies, manga, and even video games. Take 3DS game Shinrei Camera, which was released last year.
There's even ghost photography with cats. The cats aren't ghosts, of course. They're just normal cats being... cats. However, in photos, they sometimes behave like they're ghosts or spirits, and people upload them online as a wry gag.