I may be dumb...but I can't see an ,add attachment on my page. Sorry about the to an fro....
I should be there when when making or replying to a post. Although I'm not sure if it's there in the mobile version. It should be to the left of the Add attachment" button, which should be restricted since I'm not paying extra for attachment storage.
I used it to add this thumbnail. Click on it to open the full size picture in another tab.
