Taxonomy Images

Displaying Your Images in Your Theme

There are a few filters that you can use in your theme to display the image associations created by this plugin. Please read below for detailed information.

Display a single image representing the term archive

The following filter will display the image associated with the term asked for in the query string of the URL. This filter only works in views that naturally use templates like category.php, tag.php, taxonomy.php and all of their derivatives. Please read about template hierarchy for more information about these templates. The simplest use of this filter looks like:

print apply_filters( 'taxonomy-images-queried-term-image', '' );

This code will generate and print an image tag. It’s output can be modifed by passing an optional third parameter to apply_filters(). This parameter is an array and the following keys may be set:

• after (string) – Text to append to the image’s HTML.

• attr (array) – Key / value pairs representing the attributes of the img tag. Available options include: alt, class, src and title. This array will be passed as the fourth parameter to WordPress core function wp_get_attachment_image() without modification.

• before (string) – Text to prepend to the image’s HTML.

• image_size (string) – May be any image size registered with WordPress. If no image size is specified, ‘thumbnail’ will be used as a default value. In the event that an unregistered size is specified, this filter will return an empty string.

Here’s an example of what a fully customized version of this filter might look like:

print apply_filters( 'taxonomy-images-queried-term-image', '', array(
    'attr'       => array(
        'alt'   => 'Custom alternative text',
        'class' => 'my-class-list bunnies turtles',
        'src'   => 'this-is-where-the-image-lives.png',
        'title' => 'Custom Title',
        ),
    'before'     => '<div id="my-custom-div">',
    'after'      => '</div>',
    'image_size' => 'medium'
) );

Similar functionality

If you just need to get the database ID for the image, you may want to use:

$image_id = apply_filters( 'taxonomy-images-queried-term-image-id', 0 );

If you need to get the full object of the image, you may want to use:

$image = apply_filters( 'taxonomy-images-queried-term-image-object', '' );

If you need to get the URL to the image, you may want to use the following:

$image_url = apply_filters( 'taxonomy-images-queried-term-image-url', '' );

You can specify the size of the image in an option third parameter:

$image_url = apply_filters( 'taxonomy-images-queried-term-image-url', '', array(
    'image_size' => 'medium'
) );

If you need data about the image, you may want to use:

$image_data = apply_filters( 'taxonomy-images-queried-term-image-data', '' );

You can specify the size of the image in an option third parameter:

$image_data = apply_filters( 'taxonomy-images-queried-term-image-data', '', array(
    'image_size' => 'medium'
    ) );

List term images associated with a post object

When a post is being displayed you may want to display the images associated with all of the terms associated with the post. The taxonomy-images-list-the-terms filter does this. Here’s what it looks like in its simplest form:

print apply_filters( 'taxonomy-images-list-the-terms', '' );

This filter accepts an optional third parameter that you can use to customize its output. It is an array which recognizes the following keys:

• after (string) – Text to append to the output. Default value is a closing unordered list tag.

• after_image (string) – Text to append to each image. Default value is a closing list-item tag.

• before (string) – Text to prepend to the output. Default value is an open unordered list tag with an class attribute of “taxonomy-images-the-terms”.

• before_image (string) – Text to prepend to each image. Default value is an open list-item tag.

• image_size (string) – Any registered image size. Values will vary from installation to installation. Image sizes defined in core include: “thumbnail”, “medium” and “large”. “full” may also be used to get the unmodified image that was uploaded. Defaults to “thumbnail”.

• post_id (int) – The post to retrieve terms from. Defaults to the ID property of the global $post object.

• taxonomy (string) – Name of a registered taxonomy to return terms from. Defaults to category.

Here’s an example of what a fully customized version of this filter might look like:

print apply_filters( 'taxonomy-images-list-the-terms', '', array(
    'before'       => '<div class="my-custom-class-name">',
    'after'        => '</div>',
    'before_image' => '<span>',
    'after_image'  => '</span>',
    'image_size'   => 'detail',
    'post_id'      => 1234,
    'taxonomy'     => 'post_tag',
) );

Working with all terms of a given taxonomy

You will want to use the taxonomy-images-get-terms filter. This filter is basically a wrapper for WordPress core function get_terms(). It will return an array of enhanced term objects: each term object will have a custom property named image_id which is an integer representing the database ID of the image associated with the term. This filter can be used to create custom lists of terms. Here’s what it’s default useage looks like:

$terms = apply_filters( 'taxonomy-images-get-terms', '' );

Here is what php’s print_r() function may return:

Array
(
    [0] => stdClass Object
        (
            [term_id]          => 8
            [name]             => Pirate
            [slug]             => pirate
            [term_group]       => 0
            [term_taxonomy_id] => 8
            [taxonomy]         => category
            [description]      => Pirates live in the ocean and ride around on boats.
            [parent]           => 0
            [count]            => 1
            [image_id]         => 44
        )
)

As you can see, all of the goodness of get_terms() is there with an added bonus: the image_id parameter!

This filter recognizes an optional third parameter which is an array of arguments that can be used to modify its output:

• cache_images (bool) If this value is true all associated images will be queried and cached for later use in various template tags. If it is set to false, this query will be suppressed. Do not set this value to false unless you have a really good reason for doing so 🙂 Default value is true.

• having_images (bool) If this value is true then only terms that have associated images will be returned. Setting it to false will return all terms. Default value is true.

• taxonomy (string) Name of a registered taxonomy to return terms from. Multiple taxonomies may be specified by separating each name by a comma. Defaults to category.

• term_args (array) Arguments to pass to get_terms() as the second parameter. Default value is an empty array.

Here’s an example of a simple custom loop that you can use to display all term images:

$terms = apply_filters( 'taxonomy-images-get-terms', '' );
if ( ! empty( $terms ) ) {
    print '<ul>';
    foreach ( (array) $terms as $term ) {
        print '<li><a href="' . esc_url( get_term_link( $term, $term->taxonomy ) ) . '">' . wp_get_attachment_image( $term->image_id, 'detail' ) . '</a></li>';
    }
    print '</ul>';
}

Support

If you have questions about integrating this plugin into your site, please add a new thread to the WordPress Support Forum. I try to answer these, but I may not always be able to. In the event that I cannot there may be someone else who can help.

Bugs, Suggestions

Development of this plugin is hosted in a public repository on Github. If you find a bug in this plugin or have a suggestion to make it better, please create a new issue

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Need More Taxonomy Plugins?

The original author of this plugin, Michael Fields, released a handful of plugins dealing with taxonomies. Please see his WordPress.org profile for more information.