Thanks for the suggestions everybody! - we will keep improvements for the gallery 'like' system in mind when prioritizing new feature development.
For now, you can cruise through each category using the 'next image' link and hit the 'like' button on the pics you like and that will move them closer to top of the category - bringing them more exposure to eyeballs.
If you don't like it, then just don't 'like' it.. (lame pun I know)
Likes are anonymous, so nobody will make fun of you for liking something that may not be deemed cool by your peers.
Also, you can only like something once, so you don't have to remember if you already liked a pic or not - the site will let you know.
Keep the suggestions coming!