Since this is the first contest, why don't people just submit their photos no matter how much of it has been edited? Then, if there is to be a similar contest in the future, the rules can be changed accordingly to keep things fair.

Besides, if everyone keeps debating about the little stuff, there won't be any photos to choose from and this contest will have to change it's name to "The World is Ending Tomorrow so let's finally have this April 2012 Photo Contest".