Creating reliable and text-based navigation
WordPress automatically generates simple, text-based navigation that works well for both users and search spiders. Site visitors employ your website's navigation to browse your site and find content. Search engines use your navigation in a similar way, with a twist. Search engines follow the links in your navigation to find and index your pages. In addition, search engines use the text in your navigational links to reliably determine the topic of the destination page. In other words, the text you use in your navigation is a search engine ranking factor.
Tip
Avoiding image links in navigation
It is possible to create a navigation menu that employs images instead of text. However, when a search engine spider encounters an image link with no anchor text, the search engine has no text to define that element for the destination page. So, for search optimization, it's clearly better to use text links rather than image links in navigation.
Luckily...