How to change the way calendar work

[fotoman]

I would like to use the calendar but not the way it is. I wish it could use the date of the shooting of the picture not the date it was post on the blog. Can you explain me how to do that ?

my blog :

http://journalphoto.free.fr/

[DikkieBurger]

When you post an photo in your admin you have to select "post on a specific date" and then select the date of shooting. The calender takes the posting date I think