For those who use both Google Drive and Google Photos, there is sometimes some confusion about syncing between the two which can sometimes lead to photos doubling up and taking up precious space in your shared Google storage. So Google is making changes to prevent this kind of accidental deletion.
Google says the changes are being made to simplify features that caused confusion for users.
While these changes will affect any photos or videos added to either service from July 10, existing media will remain where it is, although its connection to either service will be severed - so modifying or deleting files on one won't affect the other.
It is worth noting that you'll still be able to sync photos to both Photos and Drive - but only with the Google Backup & Sync tool.
The file-syncing automatically added images from your Google Photos account to Google Drive and vice-versa.
See, since Google Drive is integrated into the Files app on Chromebooks, with automatic syncing turned on, you could access and edit/upload Google Photos images directly from the Google Photos folder in the Files app. Similarly, new photos and videos you add in Google Photos will be added to the Photos folder in Drive. Since both the products are decoupled, items copied in Original Quality will count towards your storage quota in both Drive and Photos.
Users have been able to disable the Photos folder within Drive for some time, so it seems likely that most users aren't actually using this right now (otherwise it likely wouldn't go away). Any photos that have synced between the services prior to this change will remain in both places, too.