If you want to run a photo contest over a long period of time, such as several months, it may be useful to split the contest into two phases.
In a first phase in which participants can only upload pictures and in a second subsequent voting phase. This way every photographer has the same chances of winning.
You will find the settings for this in step 4 »Advanced«. By activating the options »Allow new photos« and »Allow voting« you can start your photo contest flexibly. You can adjust this setting at any time.
In addition, the sorting of the photos can be randomized per participant. This way you can eliminate voting bias that occurs when pictures have a higher chance of getting votes at the beginning and end.