I found this article on http://www.successful-sites.com/articles/promotion-claiborne-image-links.php
I was wondering all day about using images as link on an SEO site and also how effective it would be, I want to start to use a new creative designs for my sites and this was something I was actually working on….interesting, copied and pasted some of the article if you want to read more click here
Image Links, SEO and Usability
How Image Links Can Help Build a Better User and Search Experience
By Scottie Claiborne© 2005
There are webmasters out there who believe that good design, usability, and SEO can’t co-exist in the same site; that effective SEO will ruin usability or design elements. While there are plenty of examples that seem to prove this point, it doesn’t have to be that way.
Ask for advice on building a search-friendly website, and one of the tips you will often recieve is to use text links throughout your site. Text links are read by search engine spiders and render the same regardless of the type of browser being used. They are accessible by screen readers and can be easily identified as links using CSS rollover properties. It’s great advice and you can’t go wrong using text links.
However, sometimes the most relevant phrase for a page is just too long to use in your primary navigation without looking awkward or simply including too much information for the typical site user. That’s when image links may be a better choice.
Image Links VS Text Links for SEO
Text that makes up a link is referred to as anchor text and it can be a powerful tool for search engine optimization. The text in the link tells the search engine what that page is about, and it is so powerful that pages can rank well for terms found only in links to the page and not on the page itself. (Type “miserable failure” into a Google search for an example.)
Customized text links are highly prized for their ability to improve rankings for specific search terms and it makes sense to use them on your internal pages, since those pages “count” when the engines look at links and relevance.
Image links are followed and counted as well, and the text in the alt attribute for the image serves the same function as anchor text. General theory holds that alt text isn’t as “powerful” as link text, and for good reason. Webmasters who try to “game the system” stuff zillions of phrases into their image alts in an attempt to rank better for those terms. Because it isn’t an element that is likely to be seen by users (unless they hover over an image), it can be more easily abused. In general, search engines prefer to give more weight to elements that users can see.
While it’s difficult to prove that alt text on image links is “less important” than text links, it does seem to make sense that text links have a little more “weight” than image links.
Image links can be used throughout the site for sites with awkward keyword phrases, or be used selectively for pages like “Home”, “Contact Us”, “About Us”, and other key pages that are best identified with short phrases, but can be described better using an alt attribute such as “Contact the Digital Camera Repair Service Center”.
It’s Not a Question of “Better” or “Worse”
Text and image links both serve a function and you can build a site using exclusively one or the other, and it will be fine. However, when you consider the terms that you want to rank well with and the need to balance simplicity with specific words, image links offer an alternative to wordy text links that don’t integrate into your navigation very well.
Getting a mild boost for your desired keyword phrase in an alt attribute is STILL better than getting “full” credit for “About Us”. It just makes sense to use those internal links to help identify the full topic of the page. Just remember not to go overboard when adding your alt text- only use the phrase that best describes the page.