This plugin allows you to upload images for categories and custom taxonomies, and provides a template tag to show the image(s) in your theme.

<?php if (function_exists('tclTaxonomyImage')) tclTaxonomyImage(NULL,'thumbnail'); ?> to display image <?php if (function_exists('tclTaxonomyThumbUrl')) echo tclTaxonomyThumbUrl(NULL,'thumbnail'); ?> to get URL

The WP Multiple Taxonomy Images Plugin allows you to add multiple images to a term. It supports category, tags and custom taxonomies.

It is now easy to add images to your categories, tags, or any other custom taxonomy term!

Have featured and cover images for tags, categories and custom taxonomies

Add an image to a category or taxonomy. Display a category image using either a template tag or a shortcode.