larger thumbnails?

Is it possible to get larger thumbnails or icons when you are looking into an individual folder? ie a folder that has a number of pictures in it? The slider that allows you to enlarge the icons/thumbnails is there until you click on an individual folder.

I did this http://www.macosxhints.com/article.php?story=20080325142901335 but it doesn't do anything that my puter wasn't able to do already...

Thanks in advance