Oops. On looking more closely (i.e.: looking at the full-size
image in Emailed Photos), you have the group set up as "new users
moderated."
Good catch, your group Settings page already has members
unmoderated, once past the first (few) approval(s):
So instead of manually changing your own subscription from Override:
new user moderated to Use Group Moderation Setting
you can just approve your first message(s) and let the system
automatically change your setting.
The email address of yours which is an owner of the group may be
receiving notices of your pending messages. You can simply reply
to those notices to approve your messages. But at least that will
tell you which email address (if you have several) is an owner or
moderator of the group.