i need some help.

here is my store as it is right now:
http://www.idyemyhair.com/store

what i would really like to do, is get an image rotater working for the header background image will be random every time someone visits / refreshes the page (but not animated).

so that one time coming to the page, it might be

another time it might be

or


i know there are php rotater scripts to do this, i am just not sure how to make it work with zen cart...

right now the background image is called in the stylesheet

#logoWrapper{
background-color: #ffffff;
background-image: url(../images/logo_random/logobg_magenta.png);
background-repeat: repeat-x;
height: 133px;
}

can someone please help with this???