Some assorted browser issues

I've been struggling with a few non ie browser issues and I would greatly appreciate any feedback...

First, I'm trying to replace background images on rollover events. I'm using a simple javascript function to preload the images I need, but it doesn't seem to work in mozilla or netscape. Here's the preload script I'm using:

function imgPreload() {
var imgArray=new Array();
for(i=0;i<imgPreload.arguments.length;i++) {
imgArray[i]=new Image();
imgArray[i].src='images/'+imgPreload.arguments[i];
}
}

Is this a problem with the script I'm using, or simply a matter of the way some browsers treat background images? Strangely, I've also tried using multiple layers and switching them with z-index/visibility, but it doesn't appear that these layers are being preloaded...

The other problem seems to be specific to Netscape 6. I'm using a container div inside a table (not my first choice) and swapping properties (visibility) on absolutely positioned child layers is shoving all the content down and effectively doubling the height of the container. Any clue as to what is going on?

Thanks,
Brandon