I own / manage two mailing lists which were originally on the Yahoo! system. Following a serious change in how they operated some years ago which rendered them unfit for (our) purpose, I migrated mine to a private hosting company which costs a nominal amount but does all that I require. Their home page is here:
https://www.mailmanlists.net/
I can't recall anyone posting photos in my groups, but attachments seem to be carried along without any problems at all. The moderator's interface is basic but adequate. Migration of the previous membership list to the new system was quick and painless.
Finally (and I can hardly believe that I'm writing this), a
closed Facebook group may just meet your needs for everyday communications, but I would be nervous about how it handles serious text communications.
Happy soaring,
FOR
(who enjoyed 50 years of this glorious sport before the limitations of advancing years started to be evident - to me anyway 
)