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!

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

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