Google has this service called Photos where you can just upload photos and have a photo library. They arrange them by date, you can arrange them in albums and also search them. They did not charge anything for the storage and made it very easy to get more pictures online.
So whey didn't they charge for storage? They likely wanted to have all this data for image regonition training, and for neural network training you need huge amounts of data. By just offering free space for photos to all people, you are certain to get a bunch of picture. And so I also used the service to store my images. The Android app can also directly upload all new images, I took that as a nice photo backup especially on vacation. I started to upload more images, and eventually it turned into a great dump of pictures that were sent in chats.
Recently they have changed their policy, and in six month they will start charging for storage space. They likely now have enough images online such that they can do neural network training with it. This policy change has made me question my usage of the service. And I realized that I wasn't really using it. So I stopped the automatic upload of my data to the service and then wanted to go on and delete all images which are not linked associated with an album. In some of the travel posts I had included a Google Photos album to shore more pictures, and I wanted to keep that.
As there was no option for it on the website, I thought that the API would be a good start. It would be a Sunday afternoon Python project. I started to read the API documentation, downloaded an API key and eventually started looking for a Python library. While reading up on that, I found out that one cannot modify existing content via the API. This means that my whole idea was bust. Other people have requested this feature, but Google hasn't replied there.
That is a general thing with Google. They have their intentions, and either you agree to them or fuck off. If there is a feature missing, you shouldn't hope for it to eventually come. And giving data to Google is easy. Downloading it usually is a hidden feature, and deleting it is something they try to prevent with dark UI patterns.
Since the API idea did not work out, I thought that my only option would be to delete all the images and re-upload the ones that I want to show public. The official help on that topic, Delete or restore your photos & videos wasn't helpful but insightful. You just select the items you want to delete, and then delete them. Easy, right? Just not in bulk. So if you want to delete 75.134 items in one go, well fuck you.
At least one can go to the account dashboard and take a look at the services that one uses. There I can see my usage of Google Photos. I can find something to download all my data, but I cannot find something to delete all of them in bulk. But there is a different page, one where one can delete services from the account. Curiously it only lists YouTube and Google Play Games.
I am not sure how this works under the GDPR. I thought that I must be able to download, delete and correct all my data. But perhaps it is not that fine-grained? Or that it is fulfilled as I can indeed delete all my photos, just not in bulk? And if I want bulk deletion, I'd have to delete the whole Google account? It would be an interesting legal fight with Google, but I don't care for it.