Yes you are right lots of new members need this kind of information and its wonderful to get information quickly from the forum. Helpful content.
You can read these information but I would say that you should not post in such old threads because you see last post is in 2018 which means you are replying to a thread so old and it's not good practice on forum.So avoid doing it otherwise you will violate the forum rules.
Why am I unsuccessful.
As stated for the reasons above by @Rikafip you lag the 1 merit requirement to become junior member although you have gained enough activity for it but not merits so work on it if you want to post images.Or if you really want to post images then you can have
Copper Membership which will allow you to post images instantly.But if you write quality post learning on the forum you will automatically get more then 1 merit and can post images.