I have a number of Google Photos accounts that I believe I had backed up my iPhone to over the years. However, I hadn't deleted the backed up photos from my iPhone each time, so there are many duplicates across the multiple Google Photos accounts.

Can you please help me identify the most efficient way to remove these duplicate photos that are taking up so much space? I tried to compare two accounts at a time manually but this method is extremely time-consuming, and it would really help a lot to learn a more efficient way. I know how to move photos from one account to another, but the issue is one of the two accounts containing duplicate photos is at full capacity and the other is almost full. Even if they had free space though, would the duplicates show up side by side in the account they're moved to? Because if not, it'll be hard to tell if each photo was in fact a duplicate and therefore no photos were lost somehow in the transfer process, unless I again manually check at a detailed level. Maybe I can eyeball it and send the duplicate photos to a third account with more free space, delete the same photos from both originating accounts, and then send this batch of photos back from the third account to one of the originating accounts?

This has been bothering me for a long time and I would like to do all that I can to avoid buying Google storage over and over. Thank you!