Loopholes for the win, once again
This is an example of being intentional with your words. When a constant is at stake, I would definitely suggest you being explicit about what is and what is not allowed. In this instance, you should say in the instructions, the photo has to be you! Not someone else.
Either way, this person found another hilarious loophole and exploited it to their advantage. Admittedly this baby is quite adorable and I can totally see who and how they won using this photo although I would demand royalties if I found out somehow, as this kid’s parent. Another funny story of smart people at their finest.