The pic is one of Smailholm Pele Tower. It has absolutely nothing to do with the story of Brendan Earle,I just found it on the Internet, liked it and thought it would look good. That does partly have to do with it having a lot of sky in it where I could put the title, but isn't all.
The landscape that the story is set in is described as looking like Northumberland and pele towers are mentioned once early on. There isn't one that looks like this, but I did have the idea that it would be a good scene-setting device to help the reader picture the landscape. The scene isn't as clear-skyed as I'd have liked, being as The Land is first described as having beautiful summer weather, but it being a bit darker and colder doesn't hurt for the tone of the story, which quickly turns more menacing.