This one allows me to upload an image to the assets folder to server as the thumbnail for each subcategory (aka tag). So for example, if my main collection is "books", and my tags are "fiction, nonfiction, biography", the code spits out a list of all tags with those titles, AND images with the URL: http://YOUR-STORE-CDN-URL/books-fiction.jpg, http://YOUR-STORE-CDN-URL/books-nonfiction.jpg, http://YOUR-STORE-CDN-URL/books-biography.jpg. So now you can use the assets area of the shopify theme editor to replace the "thumbnail" for your subcategory, aka your tags/tags list.

From http://ecommerce.shopify.com/c/ecommerce-design/t/pull-first-image-from-each-tag-so-subcategories-have-an-image-associated-with-link-to-tag-149029