Using WordPress ‘get_post_gallery’ PHP filter

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The get_post_gallery WordPress PHP filter allows you to modify the first-found post gallery in a WordPress post.

Usage

add_filter('get_post_gallery', 'your_custom_function', 10, 3);
function your_custom_function($gallery, $post, $galleries) {
    // your custom code here
    return $gallery;
}

Parameters

  • $gallery (array) – The first-found post gallery in the post.
  • $post (int|WP_Post) – The post ID or the WP_Post object.
  • $galleries (array) – Associative array containing all found post galleries in the post.

More information

See WordPress Developer Resources: get_post_gallery

Examples

Reverse the order of images in the first-found gallery:

add_filter('get_post_gallery', 'reverse_gallery_images', 10, 3);
function reverse_gallery_images($gallery, $post, $galleries) {
    if (!empty($gallery['ids'])) {
        $gallery['ids'] = implode(',', array_reverse(explode(',', $gallery['ids'])));
    }
    return $gallery;
}

Limit the number of images in the first-found gallery to 3:

add_filter('get_post_gallery', 'limit_gallery_images', 10, 3);
function limit_gallery_images($gallery, $post, $galleries) {
    if (!empty($gallery['ids'])) {
        $image_ids = explode(',', $gallery['ids']);
        $gallery['ids'] = implode(',', array_slice($image_ids, 0, 3));
    }
    return $gallery;
}

Remove a specific image with ID 123 from the first-found gallery:

add_filter('get_post_gallery', 'remove_specific_image', 10, 3);
function remove_specific_image($gallery, $post, $galleries) {
    if (!empty($gallery['ids'])) {
        $image_ids = explode(',', $gallery['ids']);
        $image_ids = array_diff($image_ids, array('123'));
        $gallery['ids'] = implode(',', $image_ids);
    }
    return $gallery;
}

Show a message if the first-found gallery is empty:

add_filter('get_post_gallery', 'display_custom_message_if_empty', 10, 3);
function display_custom_message_if_empty($gallery, $post, $galleries) {
    if (empty($gallery['ids'])) {
        $gallery['custom_message'] = 'No images found in this gallery.';
    }
    return $gallery;
}

Add a custom attribute data-custom-attribute to the gallery shortcode:

add_filter('get_post_gallery', 'add_custom_attribute', 10, 3);
function add_custom_attribute($gallery, $post, $galleries) {
    $gallery['data-custom-attribute'] = 'custom value';
    return $gallery;
}