Where's your evidence it's photoshopped? It's credited to "Pete Douglass/Getty Images" and Getty has a policy against photoshopped images.

It's just a photo on a day and time with particularly dramatic clouds. There's no "borderline fraud" here.

And of course it does have a lot to do with weather and lighting. Gothic horror is set in these environments at dusk and at night, in moonlight and in storms. Gothic horror doesn't generally utilize bright sunny days, so your photo isn't helping to illustrate the concept.

A building can be simultaneously majestic and inspiring during a warm sunny day, and become spooky and creepy in low light amidst the fog and cold damp.