Besides what DdmrDdmr already said, there is another way in which your images can become visible in a thread or post. If a user with the appropriate rank quotes your post in a new reply, your images will show up in their post. Sometimes they will do that themselves, especially if the image deserves to be visible. If not, it could help if you asked someone nicely to do it by mentioning it in your post. I wouldn't recommend you PM anyone to do it though as that could create problems for you. Unsolicited PMs are against the forum rules!
That's way I have seen in some
art contest where newbies are taking part and submit their entry but due to restrictions of the rank their images are not visible on the forum but other high rank members quote it for visibility and that could help him.
As suggested above @OP you could go through buying Copper Membership and post images lifting up your restrictions but you have to upload them on image hosting site first of all and then copy the BBcode and paste it here or
The other way around is that you earn 1 merit and 30 activity on your profile and as per system it will take you around one month to reach the desired activity as 14 points of activity is distributed every two weeks to active members.Earning one merit will depend on some good posts.So best wishes to you for it.