Have tried all of these. Creating the contact in mail i.e. from the sender's email address insures that the email address is valid. Turning on/off contact photos in View menu in mail does not correct the problem, contact still has no photo. Yet if I click on the email sender in mail and click on "Show Contact Card", I see the photo! Modifying the contact photo (change for monogram, emoji, etc.) does nothing. Deleting and recreating the contact does nothing to make the contact photo visible in Mail. Same problem in Mail on iPhone BTW. Yet iCloud is working just fine, a newly created or modified contact on Mac immediately appears in Contacts on iPhone. While searching for answers, I found someone noticed a problem like this when Hide My Email is used, I now think this is the problem. If I do a search in mail inbox for Hide My Email and pull up all those emails, NONE of them use the contact photo. Any solution or workaround for this, other to stop using Hide My Email (which is not an option)?