TL;DR Google has made several changes to their products and storage policies, i.e., some files that didn't consume storage quota in the past are now consuming it, and files handled in certain products are now handled in other products.
As of the beginning of October 2023, Gmail, Google Drive and Google Photos have separate file repositories. The account quota storage usage side by side is shown in Google Drive, specifically in https://drive.google.com/drive/quota.
Over the years, Google has used these repositories to consolidate the storage quota handling. For some time, Google Drive and Google Photos were integrated, i.e., Google Drive has a Google Photos folder, but this has changed.
Several services have been retired, like Picasa, Google+, and Hangouts and the way that these services were integrated has changed how the photos and movies are handled in Google accounts across the Google products.
These changes might affect the numbers shown in the quota usage numbers. Later I will add details about some notices sent to users about changes in data storage polices as some of them require users to download their data before a date and notify that files that were not consuming quota will consume it.
This is the name used to refer to the service that was made to facilitate users to download their data from most Google products.
Google Drive for Desktop
Nowadays, Google Drive for Desktop can upload files to Google Drive and Google Photos. By default, Google Drive for Desktop will upload photos and videos stored on the operative system location designated for this file. If you will customize the settings or move around photos and movies, you should be careful not to cause multiple copies of your photos and movies to be uploaded if that is not what you are looking for.
- Any file document created or uploaded through the Google Drive apps. By default, files should be added to My Drive.
- Users might authorize third-party software developers to store data using an area that the user can't access directly, like mobile backups.
- They also could be handled through Google Drive API and Google Apps Script.
- Any photos or movies uploaded through any of the Google Photos apps. By default, photos and movies in Windows, macOS, Android and iOS system folders for photos and movies are mapped to Google Photos. When installing Google Drive for Desktop and the Google Photos mobile apps the user should turn on the backup of photos and movies.
Any email message added to the user mailbox. They are added through email protocols SMTP, POP, IMAP. They also could be handled through Gmail API and Google Apps Script. When adding an attachment to Google Drive or to Google Photos this creates a copy of the attachment, and doesn't remove the file from the user's mailbox.
Retired products related to Google Photos and Google Drive