@Itsu me几乎正确。这些参数必须分别为2nd resp。第三个参数，不是第一个：

$attr = array(
    \'title\' => \'howdy partner\',
    \'alt\'   => \'a nice view of the ocean\',
);

// pick one, note 2 or 3 arguments:
the_post_thumbnail( \'post-thumbnail\', $attr );

echo("<a href=\'$p->permalink\'>". // null for current $post->ID (use within loop)
    get_the_post_thumbnail( null, \'post-thumbnail\', $attr ).
    "</a>");

尝试使用此<?php the_title(); ?>

以下是示例-

<img src="http://link-to-image" title="Image title" alt="<?php the_title(); ?>"/>

您的主题使用什么代码来显示特色图像（也称为后期缩略图）？大多数主题都是这样：

<?php the_post_thumbnail(); ?>

<?php 
    if ( has_post_thumbnail() ) { // check if the post has a Post Thumbnail assigned to it.
        the_post_thumbnail();
    } 
?>

<?php 
    if ( has_post_thumbnail() ) { // check if the post has a Post Thumbnail assigned to it.
        the_post_thumbnail(
            array(
                \'alt\' => trim( strip_tags( $attachment->post_title ) ),
            );
        );
    } 
?>

READ: WordPress Codex — Function Reference for the_post_thumbnail