API 要求您使用 URL 安全的 base64 编码.完成base64编码后，尝试将/替换为_，将+替换为-.详情见:

The API requires you to use URL-safe base64 encoding. After doing the base64 encoding, try replacing / with _ and + with -. Details at:

https://developers.google.com/admin-sdk/directory/v1/reference/users/photos/update