What you are looking at is a very crude selection of everything not-sky above the horizon with the magic wand -> cut into new layer. Notice a lot of tiny things are missing. I was to lazy to click them
Then I made a rectangle gradient with the top and bottom colors taken from the original. Placed it behind the new layer.
Then I used the clone stamp to get rid of the legs and feet in the snow. You can still see them a little bit in the most right part, as well as the most left part of the snow. There's an odd color shift there.
That's it really. You can do it yourself easily. Just make sure you get all the details in the initial selection, and do it to a higher standard. The jagged roofline is because of the catch-everything-even-remotely-white setting I used