Right now, a user must wade through each and every page of a Contest forum to rate each image. When there are many entries, this is slow and tedious. Most of the members on my site end up just ignoring half the entires and rating only the ones they like.
An option to add a rating drop-down box beneath each thumbnail on the thumbnail page would help resolve this. On my site, I have it set so that a user can see a full-size image by clicking on the thumbnail to open a Highslide box. So going to the image's page is unnecessary.
Having a rating drop-down box beneath each thumbnail would also encourage users to rate all the images instead of skipping the ones they don't like.
This would also require adding a really obvious "Submit Ratings" button somewhere on the thumbnail page.