Photos for grandparents
A grandparent joins a Chest with a display name. There is no account password to remember.
The hard part of sharing with grandparents is rarely the photo. It is the account. OurChest asks for a display name and then opens that Chest.
There is no email address and no password on that join. The invite is how they get in. A personal invite works once and then expires, so you send a fresh one when you add the next person.
The Chest keeps the file the phone uploaded. It does not make a smaller copy for the Chest, which is the usual result of dropping the same photo into a chat.