I think I can illustrate it best with showing another site.

Have a look here: http://justinmezzell.com When you see this on a larger screen and start reducing the browser windows size, you see the thumbs smoothly scaling down plus also the whitespace between the thumbs is getting smaller, so it all stays balanced. When you do this here: http://dante.swiftideas.net/portfolio-one-column-standard-style/portfolio-three-standard/ You’ll see it scales down in larger steps but also the space between the thumbs stays the same. When the screen becomes small enough and the portfolio jumps to 2 columns it does get smooth though, from there on it is ok. Not before that.