Is this true? And if yes, how can I activate it?
It should be activated by default. If your phone has backup on, you should see your photos in your google drive.
If your photos are limited to 16MB and you are using Google photos (default photo gallery app i the device)
the photos will not count for your storage limit.
Photos stored on Google photos using the High Quality setting are saved at 16 megapixels if they exceed that resolution and not a 16MB file size, the photos are highly compressed.
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