Display username under group activity media upload?

I noticed that with a multi-member group, when someone in the group uploads a picture- I guess using the rtmedia “attech media” button - that the image displayed in the group’s activity does not show any info about who uploaded it.

I think it would be VERY helpful if we could add info below the media that says who uploaded said picture.

Is there a shortcode to do this? Not sure if info is supposed to show up there and it’s just my old theme that is not displaying it - or if rtmedia currently does not attach this info (?) and so there is no way to display it?