You can now download and install the new Stg-uploader APP (Click here). This is the APP description:
This tool installs on your Sony PMCA compatible camera and allows you to upload files into Google Photos directly without using a computer. Neither of these brands endorses or is in any way associated with this tool. To install please refer to Sony-PMCA-RE
When using this application you will need to configure a connection to a WiFi access point. Once this is complete the application will prompt you to grant it an oAuth token. This token will allow it to manage your Google Photos account. Your Google username and password are not stored on the device. Your access token is obfuscated and stored on your SD card. Formatting your card will delete this token and you will have to log in again. In the case you lose your camera/card you can delete this authorization token here
This isn’t an official Sony supported APP. But as a Google Photo user I am very excited about this new feature and I am going to install this today!