Imported photos in OS X don’t appear in iCloud library

What to do when your photos don't appear in Photos.
    Related:
  • Photography
  • Apple Photos
  • iCloud Photo Library
Glenn Fleishman’s most recent books include Take Control of iOS & iPadOS Privacy and Security, Second Edition (covering iOS 15/iPadOS 15), Take Control of Your M-Series Mac, and Take Control of Securing Your Mac. In his spare time, he makes Tiny Type Museums. He’s a senior contributor to Macworld, where he writes Mac 911.