Can no longer send a photo from camera roll to a shared album

iPhone SE, iOS 14.5.1 For years I have made a new Shared Library every year with the year in the title, to share with my other half. This has always worked, and she has a shared library of photos I have sent her for each of the last 7-8 years or so. But I recently upgraded my OS (always a scary proposition with Apple) and I can no longer share photos from the camera roll, to a shared album! The option simply doesn't appear. I can email them, send them via Messages, AirDrop, Dropbox, Google Drive, and a ton of other things. But there is no option anywhere that I can see, to add the selected photos to a shared album. Album Sharing is enabled, iCloud is working, etc. How can I add a photo to a shared album in iOS 14.5.1?