What is the c-index?
"The c-index is a number between zero and 100 that aims to give a rough idea of the quality of an image. The primary use of the c-index is to enable users to sort galleries in order to bring the best images to the top. It is also used when automatically selecting images for displaying on the homepage. The c-index is not used to decide whether or not an image is promoted to the permanent image collection nor whether the image gets deleted (although it may be used to help the Praetors find good images worthy of permanent status)."
From FAQ Link
You will see the C index score on your image after about 5 - 7 votes> I do believe that is right.
<--- Somewhere in and around here ... is your "Caedes Control" (under "Control Panel") ... click to go to that page and you will see all the relevant and pertinent information for your images posted.