Add photos and videos to shared albums in iCloud
At any time, you can add more photos and videos to a shared album. When you do, subscribers to the shared album receive a notification that new items have been added.
On a Mac using Photos
See Add, remove, and edit photos in a shared album in Photos on Mac in the Photos User Guide.
On a Windows computer
Go to your shared albums.
In the iCloud for Windows app (version 10): Choose Start menu > iCloud Shared Albums.
In the iCloud for Windows app (version 7): Open File Explorer (Windows 8 or later) or Windows Explorer (Windows 7), select iCloud Photos, then double-click Shared.
Double-click the shared album you want to add photos or videos to.
Click “Add photos or videos” in the toolbar.
In the dialog that appears, do either of the following:
Drag photos or videos to the dialog from another window.
Click “Choose photos or videos.”
Videos added to a shared album can be up to 5 minutes long.