Author banners can be any dimension required, horizontal or vertical. I try to choose images that represent that person's writing as well as his/her personality. If you want to design a site around the color scheme in the author banner, I'm happy to provide a scheme of color codes when I send the banner. Banners can appear with or without text, and the text can be anything you want: name and website title, web or blog address, a quote, your titles, etc.