To quickly add/upload a large number of photos to the contest from the admin panel, we can use a special option.
To do this, go to the contest settings, then to the “Competitors” tab and find the button “Add many photos” there.
After that, the standard WordPress Media Modal will open. Here you can upload photos or select the existing from the gallery using the Ctrl and Shift keys.
Next, click the “Select” button and wait a couple of seconds – a new window will appear. Here you can edit the name of the photos, a short description and the initial number of votes. After click “Save” and photos will be added to the competition.