I joined a group (Vintage Jayco Non 5th Wheel
) and added a discussion. I had all the same facilities available as when I add a post. I was able to add a picture to my discussion.
Of course, I'm a moderator and maybe there's something's set in my profile to allow this that's not set in yours. Let me investigate.
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I browsed a number of groups and was able to find the use of links and emoticons (images) in several of the discussions. Therefore it uncertain why you are unable to do the same. Are you possibly using JOF with a mobile device?