I found a method to eliminate certain folders to show up within the Gallery. This is useful for example if you have a bunch of theme folders or mockups, and you really don't these to load within the gallery app. If you add a file zero length named .nomedia to the folder, the contents of this folder are skipped and not added to the gallery.
A zero length file is a file without any content. An easy way to make the file on cygwin/linux/droid with busybox installed (utilizing terminal prompt), is:
You can then copy this file to different directories that you would like to exclude.