• Associate image/icon to attribute options
• Specify relative/external url or pick an image from Magento Media Gallery

Install with modgit:

$ cd /path/to/magento
$ modgit init
$ modgit clone attr-opt-img https://github.com/jreinke/magento-attribute-option-image.git

or download package manually:

• Download latest version here
• Unzip in Magento root folder
• Clean cache

1. Go to Catalog > Attributes > Manage Attributes, choose an attribute with options and associate an image/icon to each option
2. In frontend templates, retrieve image src like this Mage::helper('attributeoptionimage')->getAttributeOptionImage($optionId); where $optionId could be something like $product->getColor()

I wrote an article on my blog for full extension overview, click here.