How get profile picture to show in Zoom square instead of user name

The only way I get on a Zoom call is by the link sent by the host.  A number of different hosts.

Problem:  Sometimes when I get on a Zoom call, my profile picture shows, other times my initials (TJNJT) show, but not the pic.  I seem to be initiating the calls the same way, so I cannot predict which will show.

Question: How can I control what shows in my square - picture or initials?

Thanks.

TJNJT