I tried to clone a photo contest poll unit but it doesn't copy the pictures and description.
In image polls or photo contests it is intentional that pictures are not cloned. In most cases the pictures are submitted by the participants and users did not want to have the pictures in the cloned contests.
But we are going to discuss if this can be configured.
Regarding the description I could not see a problem. Can you please send me the link of your contest to firstname.lastname@example.org?
we released today an option to be able to clone images when cloning a photo contest or image voting.