您可以在此基础上在第二个参数中设置特征图像大小document

// without parameter -> Post Thumbnail (as set by theme using set_post_thumbnail_size())
get_the_post_thumbnail( $post_id );                   

get_the_post_thumbnail( $post_id, \'thumbnail\' );      // Thumbnail (Note: different to Post Thumbnail)
get_the_post_thumbnail( $post_id, \'medium\' );         // Medium resolution
get_the_post_thumbnail( $post_id, \'large\' );          // Large resolution
get_the_post_thumbnail( $post_id, \'full\' );           // Original resolution

get_the_post_thumbnail( $post_id, array( 100, 100) ); // Other resolutions

if ( wp_is_mobile() ) {
    echo get_the_post_thumbnail( $post_id, \'large\' ); 
} else {
    echo get_the_post_thumbnail( $post_id, \'thumbnail\' ); 
}