Contest Idea, need feedback

Ok, in the past, we had a participation contest with prizes. Given to the one with the most userpoints at the end of the contest. Some argue that only the people who have plenty of time to spend on the site are the guaranteed winners. I agree with that. Some may not have chosen to participate because they knew they wouldn't have enough time to invest in it.

So here's an idea that I came up with.... ACC..... ok, hear me out.

ACC stands for Artalyst Comment Connect. Kinda like the game Connect Four.

I was thinking of having a 9x9 grid on the contest page. Under each square is an Gallery Image (hidden of course). The image is randomly selected based on images that have the least amount of comments on them. So Users, and Members, could comment on the images on the site. If they were to comment on an image that was on the ACC board, they win that slot.

I was thinking each game would have a prize. A Member could line up 3 in a row, or a User lines up 4 in a row, they win that game. After a person has won, the game restarts.

I also was thinking that this will increase participation on the site, give the paying members an increased chance to win, allow anyone to participate and win, even those who don't have extra time to spend on the site can win, just with a slightly lessened chance. Plus, to me, it sounds like fun.

Any thoughts?