One of the first things any SEO expert will tell you about designing a site for search engine crawlers is that incorrect image use can hurt your ranking.  For now, crawlers can't read text located in images (or flashy animations) so anything said inside an image is basically invisible to the search engine.  Navigation, major content, titles, and other important wording should always be text-based.  Images should be just that:  images… not words.

What better source of tips on using images in a site than the king of all search engines:  Google.

In a recap of panel discussions on images and search engines from the Search Engine Strategies conference in Chicago, the Google Webmaster Central blog has these tips for website designers and website owners:

• Don't put your text in images.  Graphics can be images, but words should be text-only.
• Use alt tags on all your images and make those alt tags descriptive and unique.
• Don't put too much information in your alt tags.
• Alt text is even more important for vital information.  If you logo or other important information is located in an image, make sure it's in the alt text as well.  Even better:  move that information out of the image.
• Check your page with images turned off.  Is the important information still there?

If images are an important part of your site (and even if they're not), consider optimizing those images for Google Image Search.  One way to do that is to sign up for the Google Image Labeler.  The Image Labeler is a system that shows users images and has them tag the content of the image.  Those tags then make it easier for Google Image Search to find your pictures.  If you're a website owner, signing up for the service will add your pictures to the rotation of images shown.  You can also sign up as a "tagger" to tag other people's images.

Images can really improve the look of a site.  But it's important to remember that images should always be secondary to content.  Unless you're a photographer, people are coming to your site to look at your content… not pictures.  If the crawlers can't see your content, you don't get indexed.  If web surfers can't find that content because it's all locked away in an image your website becomes useless.

And you don't want to have a useless website… do you?