Imageickstrip_meta 仅当image_strip_meta hook返回true，但该函数实际上并没有剥离所有概要文件。如您在功能代码中所看到的，有些是受保护的：

 /*
     * Protect a few profiles from being stripped for the following reasons:
     *
     * - icc:  Color profile information
     * - icm:  Color profile information
     * - iptc: Copyright data
     * - exif: Orientation data
     * - xmp:  Rights usage data
     */
    $protected_profiles = array(
        \'icc\',
        \'icm\',
        \'iptc\',
        \'exif\',
        \'xmp\',
    );