I am not really sure if anything running on ActivityPub really supports this. But:
On PieFed you can limit a community so that only moderators of that community can make new posts. And then everyone can comment. Comments are able to include images, though. So, if you are okay with adding those invited people as moderators, then PieFed can do what you want it to do.
First create the comm, then go to comm's settings and choose "☑ Only moderators can post".
@[email protected] , you accidentally wrote your comment in a place just like that. See here: https://nord.pub/c/fediverse/p/127183/fediverse-is-there-any-platform-in-fediverse-where-individuals-can-join-groups-just-like-fac
This thing called PieFed or Lemmy is not the same as Mastodon. \@fediverse\@lemmy.world is not a username, it’s actually what you would call a group. On PieFed/Lemmy/Mbin groups are called communities, though. But indeed, do click the link above and browse the site that opens.
I linked through my instance, nord.pub, which is mainly meant for people from Nordic countries. If you prefer something else, try piefed.social, piefed.zip, or somesuch :) But of course you can also create an account on nord.pub regardless of where you are from. At least if you know English or some Nordic language. And English you do know!
But indeed: Do browse this thing. Join some communities (that is: groups) that you like. I enjoy PieFed a lot, and for me it has healed that tickle that you’re complaining about :)
Let’s explain it this way: Microsoft has programmed a web service that is able to receive, view and send emails.
And Google has done the same, from scratch.
Email itself is merely a way different server softwares communicate with each other.
The same goes here. Some people developed a server software for receiving, viewing and sending ActivityPub content and called it Lemmy. Then other people figured it would be a nice project and did the same, from ground up, and called it PieFed.
They are the same thing. They also don’t have more content or less content. They have the precisely same content. I am writing this on PieFexd, you are reading my comment in Lemmy. And then there is also Mbin.