Enter your rating token. All of your votes get tagged with it, so several people can rate into the same file. The review token opens read-only browsing of votes instead.
Rate images by aesthetic quality. Try to ignore the image's content, even if you find it repelling.
Select the better image with A/← or D/→. If their quality is identical, use S/↓ for a tie.
This is the most important criterion. If neither image is drawn, simply choose the one you like more.
Discourage blank backgrounds.