Running out of ideas - how to delete all photos on my iPhone appearing to be a leftover from the icloud migration in Photos?
It turned out when connecting with cable and starting Image Transfer that the Camera Roll on the iPhone contained 38.000 photos (which I suppose somehow happened during my Photos-on-Mac -&gt; iCloud migration last year).
The Image Transfer program could delete them all but it took a few hours, and the backup size shrunk as expected to be small enough.
The &quot;Hey you have a new iPhone next to this one&quot;-transfer from the old iPhone to the new could then complete as expected.