I entered a Picasa photo contest a few weeks ago. My photo got to the finals, and it then became a featured photo on the Picasa website. Some luck! I added a link to my website in the caption of the photo, and in little over a week's time, the picasa photo page has received 14,000 views. Many of them click over to my site. The backlink probably won't matter much for search engines, but it does generate clicks. People also add me as a favorite, which can lead to more benefits. So, my point is, there are lots of contests out there. With a bit of luck and a good submission, you may be able get some good exposure that way.
hey rotren, congratulation on your photo . probably picasa will have a no-follow tag, but who cares, picasa is a venture of google and when you get that many clicks , it adds to the reputation of your site.should show a postive effect!