Anyone who uses Google Photos, for example to conveniently back up all pictures from their mobile phone, will sooner or later face the problem of downloading all pictures from Google Photos. The DSGVO has provided a simple solution here.
What the Basic Data Protection Regulation (in short: DSGVO) has to do with downloading the Google Photo archive: since Google has blocked most easy ways, Art. 20 DSGVO: the right to data transferability remains. Accordingly, it must be possible for a user to transfer his data (in this case the photos) in a common format to another provider.
Google offers the tool "Takeout" for this purpose: under https://takeout.google.com you can get all the data associated with a Google Account - among many other data also everything from Google Photos.
After you have selected either all albums or only certain ones (if you don't want to archive everything), you can still determine in which format (ZIP or TGZ) and in which denomination (default is 2 GB, i.e. for my 17 GB of pictures there were nine individual archive files) you want to get the data.
When the process is finished at Google and the archives are compiled, you will receive an email and can then download the individual files - unfortunately a bit unstructured and enriched with JSON files that contain meta data about the images.
If you unpack all the ZIP archives into one folder, you will get a HTML file with an overview of what is contained in the archive and subfolders sorted by date of recording. With the "exiftool" it seems to be possible to write the information from the JSON files back into the pictures, but I left this step out - I just wanted to have the pictures collected over the years back on my NAS in Replication to have.