We'll create fresh WordPress site with Google Photos Picker installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This is a plugin that enables you choose images in Google Photos and inserts them in img tags in text mode post editor. This plugin requires you create a project in Google Developers Console to have your own API credentials.
Here are steps to create your own API credentials.
Google Picker API
Authorized JavaScript origins
Settings -> Media