Like Cheese provides a number and an image of a heart beneath site images;
hover on the number to see the display names of past visitors that liked the image.
Visitors can register like/unlike your site images; heart image changes accordingly.
Uses Nextend-Facebook-Connect to allow for easy Facebook login and gain approved valuable site visitor information.
Provides additonal image fields in the media uploader.

demo http://peaceoftheocean.com/shesellsseashells
http://www.orcawebperformance.com/like-cheese-a-wordpress-plugin/

*currently this version allows for adding likes to posts
*3.0 coming soon to allow for gallery image likes, shortcodes