I sat down with my co-writer, Keith Aksland, and talked with him about a vision for a stark, visual representation of the bleak tone and setting of the story we were writing. From there, we went looking for freely available Public Domain imagery of arctic and antarctic locations.
I talked about the need to use the visual, visceral clash of blood on the snow, and he did some minor brush wizardry with photoshop to do a blood trail. I've stalked game in Canadian winters before, so I know what blood on snow looks like. Took about five tries and an hour to come up with something we both liked, but after that, we had a simple, clear visual image:
Blood on the snow, trailing off into a forbidding white arctic expanse.
Entire process was perhaps two hours, and half of that was just finding suitable imagery.
My advice for authors looking to do the same is really think about the impressions you want to distill. There's some excellent banners up on TopWebFiction right now, that tell you a huge amount about the story at a glance:
"The Gods Are Bastards" (banner here), is my personal favorite. Clean, direct, one glance at that font and coloring and you know it's a western.
"Anathema" (banner here) is damn near perfection for the banner space. Ultra clean, just enough visual space to represent some interesting character illustrations, and the rest is up for the reader to click on and find out.
"The Zombie Knight" (banner here): Not my favorite, but the tagline is catchy and the skull illustration is doing okay with the resolution it has.
"Pact" (banner here): This one is alright. I think it needs a clearer palette, the muddy colors make it hard at a glance to tell what I'm looking at. But the details are interesting. Unfortunately the tattoos look like crazy veins instead of trees, but there's not much to be done about that in that size limitation.
In turn, there's a few banners up there that I am, uh, less charitable about.
"Citadel" is stark, but a bit boring.
"Super Powereds" is in some sore need of a revamp, in my opinion.
"Midnight Moonlight": Make that bottom text bigger, and you're golden. You have a great banner waiting to happen there but trying to read that red-on-black text when it is so small is painful. Give your text a pixel border, something to make it a little easier to read overall.
That's all for now. There's a few others I rather really like and dislike, but they're not displaying at the moment on the site.