With iCloud Photos enabled, your pictures and videos sync across all connected devices via iCloud, including retaining a set that’s accessible at icloud.com. However, readers frequently write in that they see a different count of media in the Photos app on an iPhone or iPad and Photos in macOS. The reason can stem from a couple of causes, but I have some bad news at the bottom of this article.
Photos for macOS has an option to either copy media into its library or reference a photo or movie from where it sits on a drive. iCloud Photos, however, will only sync media copied into the library and under control of Photos; referenced images are ignored. The setting to choose copy versus reference is in Photos > Preferences > General as “Copy items to the Photos library.” If unchecked, anything you import via a menu item or drag into Photos to import will effectively only maintain a thumbnail of.
