Very often sites are designed with a graphic header. Often, we see a picture of the corporate logo occupying the whole dimension. Don't do it! The higher a part of a page is a terribly valuable place wherever you ought to insert your most significant keywords for best SEO. Just in case of a graphic image, that prime position is wasted since search engines can't create use of pictures. Typically, you'll come across fully absurd situations: the header contains text info, however to create its look additional engaging, it's created within the variety of a picture.
The text in it can't be indexed by search engines so it'll not contribute toward the page rank. If you want to present a logo, the most effective approach is to use a hybrid approach – place the graphic logo at the highest of every page and size it so it doesn't occupy its entire dimension. Use a text header to create up the rest of the dimension.