Category index featured image

What I did was; using the Taxonomy Images plugin to associate an image with each category, then to my theme’s header.php, below the <a> line in the above code;

<?php 
            $image_id = apply_filters( 'taxonomy-images-queried-term-image-id', 0 );
            if ( is_category() && ! empty( $image_id )):
             print apply_filters( 'taxonomy-images-queried-term-image', '',  
                array(
                'image_size' => 'header'
            ) );
            else : ?>

And add <?php endif; ?> below the endif ‘end check for featured…’

and defined the header image size in functions.php with

add_image_size( 'header', 960, 260, true );