How to get Java to fade in from white, not black

I have a simple fading gallery with five images. Before the first image fades in, the java shows a black block - no image there, so black. How can I make this white, rather than black?

 

Find the id/class of the container and change it's background color.
But that could be anywhere, we need to see the code first.

It might look something like this:

<div id='gallery' style='background-color: #000;'></div>

Code (markup):

Or the color may be in a stylesheet:

#gallery {
   background-color: #000;
}

Code (markup):

Or it could even be the background color of the main page.