This type of optimisation can be particularly important when imagery is integral to your business offering, for example if you are a photographer, designer or artist.

How to Optimise Images
Ann Smarty has written an excellent post on how to optimise images for people, Social Media and the Search Engines, see: http://www.seosmarty.com/image-seo/

Another Thought
If you really want to get your images out to a wider audience sites such as Flikr.com can also be a great way of posting your images and putting them in front of a large audience of image enthusiasts.