Biggy offers a variety of headers, from a minimal light to a dark style. Depending on which type of page you are viewing, and if it has a featured image, you also get the option to have a photographic header. Photo headers will be based on posts, pages, and templates used.
For the front page, you also have the WordPress Custom Header which can rotate through several images that you upload. So each time you refresh the front page or revisit, the image will change.