How to specify link text when the link is an image?

I'm making an web shop (my first one), and on the front page my client wants banners with their current hot deals. Naturally I want Google and other r开发者_如何学编程obots to be able to understand what these links are all about. I think (but I'm not sure) that Google will treat my <a> tag better if it will have some relevant text inside it. But a banner is just an image. How do I put text there? Could a <span style="display:none"> work? Maybe the title="" attribute?

Added: OOps, forgot to say - I place the image as a background image to my <a> tag - this gives me vertical centering. So there are no <img> tags.

Google will index the Alt text property on your image. http://www.search-marketing.info/organic-listings/img-alt.htm

I've always done <a href="whatever.html"><span style="display:none;">My SEO text</span></a>. I've learned this trick from the CSSZenGarden. Another way to "hide" text involve setting a text-indent: -100000em;, and I'm sure there are some more.

It works at the CSS Zen Garden, google does not penalize it. search for "the beauty of css design" and you'll see that it gets indexed at google.

Google cant crawl images but Google can index alt text so try to link the images with alt-abbr.