By renaming your image the main keyword to make the post or page, you trick google search into thinking there is far more relevant keywords and content on your page. Keywords aren't always easy to use within the actual body with the post naturally, so renaming images is really a handy way of hiding them from the readers, but letting bing know usually are there. In order to obtain quality ... rank higher in various search engines. To look natural, you also must have some No Follow sites. We might your incoming links came from Do Follow sites, various search engines will view this as unnatural.