iCloud shared album does not update

Hi

I have created an album in Photos on my Macbook with pictures from a vacation.

I then shared the album with my girlfriend who could then view the pictures on her iPhone - Great so far.

However, I later discovered som more photos from the vacation and added them to the album, but she cannot see these new photos.

Shouldn't she be able to? Or am I missing something?

Thanks, Søren