Skyline was my choice for the hearder challenge this week. For me a skyline image needs some visual interest in both the sky and the ground below, though one aspect may dominate and make a beautiful image. For my headers I prefer a horizontal image, as I also prefer that the beginning of my post be visible without scrolling. The above image was taken December 22 with the idea of using it as a header. it is the view of downtown Frederick from Baker Park.
I would crop this one below the clock to use as a header. This spire has appeared on my blogs several times, but not from this view.
This one also became a header for my other blog, Lew's pics. And below is a possible header of a winter sun setting over an empty baseball field.