There are several limits to sharing photos as shared albums, because it does not count against your free iCöoud allowance, see this page:
iCloud: My Photo Stream and iCloud Photo Sharing limits
These are the iCloud Photo Sharing hourly and daily limits:
- Maximum combined number of photos and videos from all contributors per shared album, per hour: 1000
- Maximum combined number of photos and videos from all contributors per shared album, per day: 10,000
These sharing limits are separate from the upload limits above. For example, in the same day you could upload 10,000 photos to My Photo Stream, then share those 10,000 photos or 10,000 other photos.Some additional limits for shared albums:
- Maximum shared albums an owner can share: 100
- Maximum shared albums a user can subscribe to: 100
- Maximum subscribers per shared album: 100 (the number of subscribers on each shared album)
- Maximum combined number of photos and videos from all contributors in any one shared album: 5000
- Maximum number of comments per photo or video in a shared album: 200 (a comment can be either a like or a text entry)
- Maximum characters per comment: 200
- Maximum number of invites a shared album owner may send per day: 200