取特色图片

the_post_thumbnail(); // Without parameter ->; Thumbnail
the_post_thumbnail( 'thumbnail' ); // Thumbnail (default 150px x 150px max)
the_post_thumbnail( 'medium' ); // Medium resolution (default 300px x 300px max)
the_post_thumbnail( 'medium_large' ); // Medium-large resolution (default 768px x no height limit max)
the_post_thumbnail( 'large' ); // Large resolution (default 1024px x 1024px max)
the_post_thumbnail( 'full' ); // Original image resolution (unmodified)
the_post_thumbnail( array( 100, 100 ) ); // Other resolutions (height, width)

判断是否有设置过特色图片

// check if the post or page has a Featured Image assigned to it.
if ( has_post_thumbnail() ) {
    the_post_thumbnail();
}

取缩略图地址

if ( has_post_thumbnail()) {
    $large_image_url = wp_get_attachment_image_src( get_post_thumbnail_id(), 'large');
    echo $large_image_url[0];
}

https://blog.wpjam.com/m/get-featured-image-source/

https://developer.wordpress.org/themes/functionality/featured-images-post-thumbnails/