Cannot access iCloud albums on iphone

Hi all - I recently started using the iCloud photo library. I noticed when I sign into iCloud.com it is a mirror image of my Mac OS Photos app and I can access every picture that is on my computer. However, on my iPhone, for some reason, despite making sure the iCloud photo library is turned on, I cannot access the pictures from iCloud, I can only access the pics that were taken on my phone. I have looked under "albums" in the photos app on the iPhone.

Any ideas?

Thanks in advance