Feed Post Thumbnail

PBR

Does the RSS feed still validate with this plugin enabled?

Yep, we add the proper XML namespaces for that. Everything just works as expected!

Any way to force the plugin to always add a certain thumbnail size?

Yes, the plugin has two filters available for this:

// Filters the size on media:content tag. Defaults to 'full'.
add_filter( 'wp_feed_post_thumbnail_image_size_full', function( $size ) {
    return 'large'; // Return any registered image size.
}, 10, 1 );

// Filters the size on the media:thumbnail tag. Defaults to 'thumbnail'.
add_filter( 'wp_feed_post_thumbnail_image_size_thumbnail', function( $size ) {
    return 'medium'; // Return any registered image size.
}, 10, 1 );

Can I change which images are shown?

Yes, the plugin has two filters available for this:

// Filters the featured image attachment post object.
add_filter( 'wp_feed_post_thumbnail_image', function( $thumbnail ) {
    return ''; // Return an empty string or another attachment post object.
}, 10, 1 );

// Filters the array of attachment post objects. Defaults to featured image post object if exists.
add_filter( 'wp_feed_post_thumbnail_images', function( $images ) {
    $attachment_id = '123';
    $images[] =  get_post( $attachment_id ); // Additional attachment post object.
    return images;
}, 10, 1 );

Can I change the title, description or author shown with the image?

Yes, there is a filter for each of these things:

// Filters the title on the media:title tag. Defaults to attachment title.
add_filter( 'wp_feed_post_thumbnail_title', function( $title ) {
    return 'Override title'; // Return any plain text.
}, 10, 1 );

// Filters the text on the media:description tag. Defaults to attachment description.
add_filter( 'wp_feed_post_thumbnail_description', function( $description ) {
    return 'Same description for all images'; // Return any plain string.
}, 10, 1 );

// Filters the name of the author on the media:copyright tag. Defaults to attachment author.
add_filter( 'wp_feed_post_thumbnail_author', function( $author_name ) {
    return 'Matt'; // Return any plain string.
}, 10, 1 );