I know it is a contest for fun, and there was no one "cheated" or harmed, but to have a contest stating rules means either abide by them or don't have any. You might not be upset, but you aren't the only #2. And what about the next time? Someone else might not be as understanding as you...THAT is why there are rules.
I would suggest you ammend the rules to include the ability to post WIPs in your own galleries then (eliminating anonymity completely) or the ability to take existing renders, change something-anything-and  rerender it as new to be able to submit it. Something presently I mistakenly took as grounds for dissqualification by reading (in bold too) what is there now. 
Sorry, but I'm sticking to my guns on this point, if only as a matter of principle. 
I believe this was blatantly wrong. I cannot see it as anything else.
I know these are your contests and your rules, fine. Make them clear and concise, and fair for everyone else. That is all I am trying to convey.