Missing Photo Captions

How have you imported the photos from the iPhone? Did you download them directly via a USB connection, or did you sync them with iCloud Photos?

iCloud Photos will sync the captions, but the direct import will just import the original files, without any added metadata.

How did you add the captions? On your iPhone? I don't usually caption them there, but it does work for me. Do they appear properly on your iPhone?

Oops, léonie, same time same place. These were my thoughts:

Of course, we know that it does work. The question is, "why isn't it working for you?" You don't say what version of iPhone you have, or what iOS your are running. I see that your Mac is using Sierra, a pretty old OS, and I'm not sure if captioning was fully supported back then. If you give us this information, someone might be able to help.

Could you include a screenshot of the caption and picture on the iPhone and in Photos? That, too, might help.