Taxonomy Term Image

An example plugin for adding an image upload field to taxonomy term edit pages, and an example of the new taxonomy term meta data added in WordPress 4.4. This example IS NOT compatible with any version of WordPress lower than 4.4, it is meant to be used as an example only.

How to use within a theme or plugin:

Setup file:

1. Delete plugin meta data at the top of taxonomy-term-image.php
2. include_once taxonomy-term-image.php

Hooks

filter taxonomy-term-image-taxonomy:

Change the taxonomy targeted by the plugin. By default, the category taxonomy is the only taxonomy targeted. You can change this to tags if you'd like following the example below:

	function the_term_image_taxonomy( $taxonomy ) {
		// use for tags instead of categories
		return 'post_tag';
	}
	add_filter( 'taxonomy-term-image-taxonomy', 'the_term_image_taxonomy' );

Alternatively, the plugin can target more than one taxonomy by providing it an array of taxonomy slugs:

	function the_term_image_taxonomy( $taxonomy ) {
		// use for tags and categories
		return array( 'post_tag', 'category' );
	}
	add_filter( 'taxonomy-term-image-taxonomy', 'the_term_image_taxonomy' );

filter taxonomy-term-image-labels:

Change the field and button text.

	function the_taxonomy_term_image_labels( $labels ) {
		$labels['fieldTitle'] = __( 'My Super Rad Plugin', 'yourdomain' );
		$labels['fieldDescription'] = __( 'This plugin is cool, and does neat stuff.', 'yourdomain' );

		return $labels;
	}
	add_filter( 'taxonomy-term-image-labels', 'the_taxonomy_term_image_labels' );

filter taxonomy-term-image-meta-key:

Change the meta key used to save the image ID in the term meta data

	function the_taxonomy_term_image_meta_key( $option_name ) {
		// store in term meta where term meta key is = 'my_term_meta_key'
		return 'my_term_meta_key';
	}
	add_filter( 'taxonomy-term-image-meta-key', 'the_taxonomy_term_image_meta_key' );

filter taxonomy-term-image-js-dir-url:

Change where the js file is located. (no trailing slash)

	function my_taxonomy_term_image_js_dir_url( $option_name ) {
		// change the js directory to a subdirectory of this hook
		return plugin_dir_url( __FILE__ ) . '/js';
	}
	add_filter( 'taxonomy-term-image-js-dir-url', 'my_taxonomy_term_image_js_dir_url' );

show image on archive template

Term Image IDs are automatically attached to terms that are passed through the get_term and get_terms filters as the ->term_image property.

	$term = get_term( 123, 'category' );

	if ( $term->term_image ) {
		echo wp_get_attachment_image( $term->term_image, 'full' );
	}

In order to retrieve the term image on an archive page:

	$term = get_queried_object();

	if ( $term->term_image ) {
	    echo wp_get_attachment_image( $term->term_image, 'full' );
    }

References:

Articles:

• Using Media Uploader in plugins
• Introduction to WordPress term meta

Code References:

• Plugin Hooks
  • action admin_init
  • action admin_enqueue_scripts
  • function wp_register_script
  • function wp_localize_script
  • function wp_enqueue_script
• Term Meta Data
  • function register_meta
  • function get_term_meta
  • function update_term_meta
  • function delete_term_meta
• Taxonomy Hooks
  • action create_{$taxonomy}
  • action edit_{$taxonomy}
  • action {$taxonomy}_add_form_fields
  • action {$taxonomy}_edit_form_fields
  • filter get_term
  • filter get_terms
  • filter get_object_terms