By hosting your images at one of the leading online photo/image hosting services such as Picasa, Flickr, Photobucket and others your search engine visibility will likely improve. Why? Most of those services provide a spot for a link back to your website providing customers another means of entry into your site and showing Google and other search engines a "high quality inbound link".
We're big fans of Google's Webmaster Tools. Check out a blog post from Google about Webmaster Tools and how inbound links can improve your site's search results ranking.
http://googlewebmastercentral.blogspot.com/2008/10/good-times-with-inbound-links.html
