They did that over on the Deer & Deer Hunting website last season also.

Except theirs was a weekly contest, and some of the pictures were pretty awful, but kinda cool seeing how far off you really were.

I have a tendency to miss 5-15" lower than the actual gross.....rather be low than high when guesstimating, so when you tell someone that you saw a "BIG" one they tend to believe you......