A picture is worth a thousand words. Unfortunately, when it comes to major search engines (which are still primarily text-based), a picture is worth a lot of blank space. Does this mean you shouldn’t use images on your site if you want to rank in search? Not at all. Just keep some simple things in mind when adding those images to your pages. As a bonus, these tips help not only with seach engine robots, but with Jane as well! You want your site to be accessible in screen readers, to those who have images turned off in their browsers, and to those who have slow connections or are on mobile browsers and may have trouble loading images.
For the recent webinar I did on link building, I was researching how use of social networks can help with SEO. Businesses can gain all kinds of value from social networking: build brand recognition, increase customer loyalty, help them be responsive to customer issues and better understand the audience, get more links and exposure… Er, etc.
But one value that is sometimes overlooked is increased opportunity to rank. I wrote about this a bit in the context of reputation management. But it can work for any search query you want to rank for. You can capture more positions in the SERPs if in addition to having content from your site rank, you can get content from social networks that point to your content to rank.
You can easily see this with Flickr.
Take, for instance, this article I wrote for Search Engine Land about Hakia’s Meet Others feature. Here’s an image, hosted on Flickr, that I used in the article:

And here’s that image at position #13 (and #14) for a Google search for Hakia Meet Others:

So, sure. Hosting the image on Flickr is great just for storage and organization. It helps me share what I’m doing with anyone who’s interested and who’s added me as a Flickr contact. I can get traffic from the link. But it’s also giving me another opportunity (in addition to the article itself, which is ranked #3 for the query) to rank. Sounds good to me.