You can not post images directly until you reach some certain rank as already explained by some members above. Someone has quoted you already so your images are now visible.
But you are not eligible to participate in the contest, I guess you didn't the rules that says you must at least a Jr. Member rank to participate.
It seems obvious that maybe the op reason for joining the community is to participate in the contest so funny I guess because I don't see the reason for such curiosity of joining that contest without even proper reading of the rules, there are more important engagements that a newbie should be involved with in the forum other than the contest considering his registration date I just hope that he will learn from the replies he is getting now and improve in other to avoid such mistakes of not reading rules in whatever he might want to participate in the future.