调查一下set_theme_mod():

创建或更新当前主题的修改设置

和get_theme_mod():

检索当前主题的修改设置

有了它，您应该能够获得徽标：

$custom_logo_id = get_theme_mod( \'custom_logo\' );
$logo = wp_get_attachment_image( $custom_logo_id, \'full\' );

$attachment_id = 12;
set_theme_mod( \'custom_logo\', $attachment_id );