我想复制一个图像并用新名称将其转换为BW，但当我尝试用imagejpeg():

PHP警告：imagejpeg（/srv/www/raquelfriera.test/current/web/app/uploads/2018/02/2018/02/one-year-womens-performance-10-400x266-bw.jpg）：无法打开流：没有此类文件或目录

我根据自定义大小创建图像img-400.-bw 在文件名的末尾使用imagejpeg保存它（$image，$dest）wp_generate_attachment_metadata. 这样，我可以在上载或wp media regenerate.

这是整个功能：

function bw_filter($meta) {
  $path = wp_upload_dir();
  /* get dirname of file to get correct date folder */
  $subdir = trailingslashit(dirname($meta[\'file\']));
  /* get basedir on path to get uploads folder */
  $file = trailingslashit($path[\'basedir\']).$subdir.$meta[\'sizes\'][\'img-400\'][\'file\'];
  $str = str_replace(".", "-bw.", $subdir.$meta[\'sizes\'][\'img-400\'][\'file\']);
  $dest = trailingslashit($path[\'basedir\']).$subdir.$str;
  list($orig_w, $orig_h, $orig_type) = @getimagesize($file);


  switch ($orig_type) {
    case IMAGETYPE_GIF:
      $image = imagecreatefromgif($file);
      imagefilter($image, IMG_FILTER_GRAYSCALE);
      imagefilter($image, IMG_FILTER_CONTRAST, -30);
      imagegif( $image, $dest );
    break;
    case IMAGETYPE_PNG:
      $image = imagecreatefrompng($file);
      imagefilter($image, IMG_FILTER_GRAYSCALE);
      imagefilter($image, IMG_FILTER_CONTRAST, -30);
      imagepng( $image, $dest );
    break;
    case IMAGETYPE_JPEG:
      $image = imagecreatefromjpeg($file);
      imagefilter($image, IMG_FILTER_GRAYSCALE);
      imagefilter($image, IMG_FILTER_CONTRAST, -30);
      imagejpeg( $image, $dest );
    break;
  }
  return $meta;
}
add_filter(\'wp_generate_attachment_metadata\', __NAMESPACE__ . \'\\\\bw_filter\',10,2);