For all of the talk of ecosystems, it was easier to share from my Apple Photos library to Micro.blog and to Instagram from my iPhone. Not my iPad, for which there is no native Instagram app, and for which the work-alikes did not allow multiple selections. So, while my iPhone was charging, I downloaded the iPhone app to my iPad, did the pixel doubling so I could type, and did the work that way.
There are probably more ways to do this, and really I wanted to do it elegantly from my MacBook Air, however I didn’t perceive a faster method than exporting and uploading, and I chose not to do that.
I feel that this might be a driver behind Catayst apps and unifying the underlying silicon.