How to make your own selvage dots

You know those cool dots on the selvage of fabric? You use them to help you find matching colors when fabric shopping, right? What if you could have those dots for any picture?
http://www.cssdrive.com/imagepalette/index.php
This photo website makes color samples from your photos. Or, if you can scan your fabrics, from your whole stash.
Called Colors Palette Generator, this cool tech tool "lists" every hue in a picture you upload, and even lets you sort them by grade..