您可以使用post_gallery 筛选作业并替换wp_get_attachment_link() 具有wp_get_attachment_image(). 类似于：

add_filter( \'post_gallery\', \'post_gallery_wpse219434\', 10, 2 );
function post_gallery_wpse219434( $output, $attr) {
    global $post, $wp_locale;

    static $instance = 0;
    $instance++;

    // We\'re trusting author input, so let\'s at least make sure it looks like a valid orderby statement
    if ( isset( $attr[\'orderby\'] ) ) {
        $attr[\'orderby\'] = sanitize_sql_orderby( $attr[\'orderby\'] );
        if ( !$attr[\'orderby\'] )
            unset( $attr[\'orderby\'] );
    }

    extract(shortcode_atts(array(
        \'order\'      => \'ASC\',
        \'orderby\'    => \'menu_order ID\',
        \'id\'         => $post->ID,
        \'itemtag\'    => \'dl\',
        \'icontag\'    => \'dt\',
        \'captiontag\' => \'dd\',
        \'columns\'    => 3,
        \'size\'       => \'thumbnail\',
        \'include\'    => \'\',
        \'exclude\'    => \'\'
    ), $attr));

    $id = intval($id);
    if ( \'RAND\' == $order )
        $orderby = \'none\';

    if ( !empty($include) ) {
        $include = preg_replace( \'/[^0-9,]+/\', \'\', $include );
        $_attachments = get_posts( array(\'include\' => $include, \'post_status\' => \'inherit\', \'post_type\' => \'attachment\', \'post_mime_type\' => \'image\', \'order\' => $order, \'orderby\' => $orderby) );

        $attachments = array();
        foreach ( $_attachments as $key => $val ) {
            $attachments[$val->ID] = $_attachments[$key];
        }
    } elseif ( !empty($exclude) ) {
        $exclude = preg_replace( \'/[^0-9,]+/\', \'\', $exclude );
        $attachments = get_children( array(\'post_parent\' => $id, \'exclude\' => $exclude, \'post_status\' => \'inherit\', \'post_type\' => \'attachment\', \'post_mime_type\' => \'image\', \'order\' => $order, \'orderby\' => $orderby) );
    } else {
        $attachments = get_children( array(\'post_parent\' => $id, \'post_status\' => \'inherit\', \'post_type\' => \'attachment\', \'post_mime_type\' => \'image\', \'order\' => $order, \'orderby\' => $orderby) );
    }

    if ( empty($attachments) )
        return \'\';

    if ( is_feed() ) {
        $output = "\\n";
        foreach ( $attachments as $att_id => $attachment )
            $output .= wp_get_attachment_link($att_id, $size, true) . "\\n";
        return $output;
    }

    $itemtag = tag_escape($itemtag);
    $captiontag = tag_escape($captiontag);
    $columns = intval($columns);
    $itemwidth = $columns > 0 ? floor(100/$columns) : 100;
    $float = is_rtl() ? \'right\' : \'left\';

    $selector = "gallery-{$instance}";

    $output = apply_filters(\'gallery_style\', "
        <style type=\'text/css\'>
            #{$selector} {
                margin: auto;
            }
            #{$selector} .gallery-item {
                float: {$float};
                margin-top: 10px;
                text-align: center;
                width: {$itemwidth}%;           }
            #{$selector} img {
                border: 2px solid #cfcfcf;
            }
            #{$selector} .gallery-caption {
                margin-left: 0;
            }
        </style>
        <!-- see gallery_shortcode() in wp-includes/media.php -->
        <div id=\'$selector\' class=\'gallery galleryid-{$id}\'>");

    $i = 0;
    foreach ( $attachments as $id => $attachment ) {
        //$link = isset($attr[\'link\']) && \'file\' == $attr[\'link\'] ? wp_get_attachment_link($id, $size, false, false) : wp_get_attachment_link($id, $size, true, false);
        $link = wp_get_attachment_image($id, $size);

        $output .= "<{$itemtag} class=\'gallery-item\'>";
        $output .= "
            <{$icontag} class=\'gallery-icon\'>
                <a></a>
                <span>
                $link
                </span>
            </{$icontag}>";
        if ( $captiontag && trim($attachment->post_excerpt) ) {
            $output .= "
                <{$captiontag} class=\'gallery-caption\'>
                " . wptexturize($attachment->post_excerpt) . "
                </{$captiontag}>";
        }
        $output .= "</{$itemtag}>";
        if ( $columns > 0 && ++$i % $columns == 0 )
            $output .= \'<br style="clear: both" />\';
    }

    $output .= "
            <br style=\'clear: both;\' />
        </div>\\n";

    return $output;
}

   $output .= "<{$itemtag} class=\'gallery-item\'>";
    $output .= "
        <{$icontag} class=\'gallery-icon\'>
            <a></a>
            <span>
            $link
            </span>
        </{$icontag}>";
    if ( $captiontag && trim($attachment->post_excerpt) ) {
        $output .= "
            <{$captiontag} class=\'gallery-caption\'>
            " . wptexturize($attachment->post_excerpt) . "
            </{$captiontag}>";
    }
    $output .= "</{$itemtag}>";

extract(shortcode_atts(array(
    \'order\'      => \'ASC\',
    \'orderby\'    => \'menu_order ID\',
    \'id\'         => $post->ID,
    \'itemtag\'    => \'dl\',
    \'icontag\'    => \'dt\',
    \'captiontag\' => \'dd\',
    \'columns\'    => 3,
    \'size\'       => \'thumbnail\',
    \'include\'    => \'\',
    \'exclude\'    => \'\'
), $attr));