To estimate the storage requirements for Google Photos on Pixel phones, we must take into account the size of the photos and how often they are taken. Google Photos compresses images to 'high quality,' which typically average around 1 MB each. If we assume an average user takes 5 photos daily, this amounts to 5 MB of storage used per day. In total, this would result in approximately 1.8 GB of storage needed over the course of a year (5 MB * 365). However, Google provides free 'high quality' photo storage for users of Pixel devices. As a result, even though Pixel phone users may generate around 1.8 GB of photo data annually, it does not count towards their Google account storage limit.